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1/4 Scale Salto**

Posted: 12 Jul 2020, 17:09
by Peter Balcombe
Although the H101 Salto was originally available in the Pat Teakle Sailplanes range, the fuselage mould had been damaged beyond repair at some time before Cliff took over the reins, so sadly this aerobatic model has not been available.
However, Cliff has recently managed to obtain an unused original fuselage & John Hall has worked his magic on it to produce a new mould, plus while he was at it, modify the wing section from the original Ritz1 variety.

After lots of discussion & comments/advice from other modellers, plus the desire to make a model that is relatively easy to build, the new fuselage has an HQW2.5/12 wing section, giving a thin section with no need for washout.
Although the use of substantial carbon joiners was considered, it was decided in the end to go for a pair of 15mm steel joiner strips mounted in wing tubes & which just fit between the main spars. Dihedral is provided via a ‘scissors’ type joiner fuselage box which takes the wing joiners in an interleaved arrangement.

The main spar assembly is made up as full box section at the root, changing to a 'C' beam at the aileron taper break. Scale rotating TE airbrakes are used & the built-up structure is sheeted in 0.8mm ply (or perhaps GRP sheet) prior to glassing the finished wing. Time will tell how this aspect pans out

Anyway, with a set of laser cut parts supplied by Cliff, the build of the first wing has just started.
The pics show the initial build of the RH wing root end, with all normal ribs attached to the lower main spar & rear spar web + root end rear web doubler. The Liteply false LE is notched into each rib & the notched rear spar web also helps locate everything - which is just as well as for some reason, the plan has printed undersize :(
4 ply angled ribs will be added at the root end to form the edges of the 2 TE brake cutouts. Again, these notch into the structure to take up the correct positions.

The front spar web (again doubled at the root end) will be slotted in shortly prior to the section of root ribs between the spar webs being removed to insert the joiner tub assembly (2 brass tubes + 2 spacers, reversed between wings to get interleaved joiners in fuselage ;) )
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Re: 1/4 Scale Salto

Posted: 13 Jul 2020, 12:08
by Peter Balcombe
With the outstanding lower rear spar inserted to complete the basic framework, attention turns to the joiner assembly.
This is made up using interleaved brass tubes and 3mm spacers, epoxied together to form a solid block as shown. The root rib sections between the spar webs were then removed using a razor saw & tidied up with a sturdy file to leave a clean slot.
Note that the joiner assembly needs to be cleaned up to reduce its overall thickness to that of the joiner tubes (16mm) as it will be a very neat fit between the spars at the outer end, so any thicker & the upper spar will not sit down correctly.

Once happy with everything the joiner can be epoxied in place.
Note that the joiner tube arrangement will need to be reversed for the 2nd wing In order to allow the 4 joiner strips from both wings to interleaved in the fuselage without having one wing in front of the other.
(I arranged the forward brass tube at the front on my RH wing, so the spacer will need to be at the front on the LH wing.)
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Re: 1/4 Scale Salto

Posted: 13 Jul 2020, 16:35
by Peter Balcombe
Top main spar glued in place using epoxy (mostly to get a really good bond in the joiner area).
Have also added a strip of 0.8mm ply at lower TE to tie the vulnerable rib ends together (temporarily supported using a spruce strip as a straight edge whilst the glue dries.
I will probably add a similar ply strip on the top to finish forming the TE before I start to address the TE airbrakes. (The wings are likely to be sheeted with 0.8mm ply anyway).
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Re: 1/4 Scale Salto

Posted: 13 Jul 2020, 19:00
by John Vella
Peter, neat work. Why are you covering the wings with 0.8mm ply? I have covered 2 models with 0.4mm ply which does a good but expensive job. Regards John.

Re: 1/4 Scale Salto

Posted: 13 Jul 2020, 19:15
by Peter Balcombe
Hi John,
I designed the built-up wing structure on the basis of 0.8mm skins because:
(a) I didn’t have enough spare thickness to get any sensible joiner/spar in with my normal 1/16” balsa sheet skins
(b) With a faster aerobatic type of model, I wanted a firm wing surface
(c) I wanted to use a firm sheet surface for the scale type TE airbrakes
(c) There was the possibility of 0.5mm ‘ish’ grp sheet being made available.

However, as the model is almost certain to be glassed anyway, then a glassed 0.4mm skin is probably another practical option & possibly easier to apply on a smallish model ;)

Re: 1/4 Scale Salto

Posted: 13 Jul 2020, 21:06
by John Vella
Peter, the scale t.e airbrakes are a great idea and are a big feature on the full size. The 0.4mm ply skins glassed will do the job well with plenty of torsional stiffness for the aerobatics. Regards John.

Re: 1/4 Scale Salto

Posted: 27 Jul 2020, 16:16
by Peter Balcombe
Back to the Salto at last, so a quick update.
Having completed the tailplane design, Cliff has cut the parts & the initial build has started.
The pic below shows the main structure, to which will be added a solid ruddervator. Each tailplane half carries its own servo, with a short external pushrod to the ruddervator horn. The tailplane attachment is via rear joiner & short front incidence dowel. The main joiners are staggered in each tailplane to allow the fuselage tubes to be crossed.
Cliff has come up with a neat single servo connector housing which can be fitted flush in each fuselage tailplane root, complete with standard servo connector. The tailplane servo connector can be easily plugged into this during rigging.

On the wing front, the only recent progress to report is the addition of the brake hinge line spar doubler strips between each rib (bevelled in the brake sections), plus fitting of 1/16" balsa sheet lower surface covers between each rib in the brake areas - the brake lower surfaces will hopefuly close to lie flush with these covers in due course.
I've decided to fit additional angled riblets to define the brake end faces before adding any sheeting in order to have a tidy facing to each brake and wing surround and also to hopefully be able to remove the brake by cutting between the riblets.

I think that I will go with Ian's suggestion of using 0.4mm ply sheeting & hope that the lower brake blade forward surface will be stiff enough once glassed, particularly as this area is likely to be exposed to ground contact if the brakes are not closed before touchdown.

I'm still trying to sort out the best assembly sequence to try to ensure a best fit & operation, whilst not having to go back into the structure :?
Tailplane half1_small.jpeg
Tailplane build2_small.jpeg
Tail servo connector.jpeg
Wing lower brake closures.jpeg

Re: 1/4 Scale Salto

Posted: 28 Jul 2020, 08:31
by john greenfield
Peter Balcombe wrote: 13 Jul 2020, 19:15 Hi John,
I designed the built-up wing structure on the basis of 0.8mm skins because:
(a) I didn’t have enough spare thickness to get any sensible joiner/spar in with my normal 1/16” balsa sheet skins
(b) With a faster aerobatic type of model, I wanted a firm wing surface
(c) I wanted to use a firm sheet surface for the scale type TE airbrakes
(c) There was the possibility of 0.5mm ‘ish’ grp sheet being made available.

However, as the model is almost certain to be glassed anyway, then a glassed 0.4mm skin is probably another practical option & possibly easier to apply on a smallish model ;)
Hi Peter

Just a few comments on ply wing skinning.
Please be aware that most 0.8mm ply sold in the UK is actually 0.95mm thick (event though marked as 0.8mm). This adds a considerable amount of extra weight to the model as 0.95mm ply is almost 20% heavier than 0.8mm.
).4mm ply, even if glassed is still quite prone to splitting with rough handling. Splits start in the middle of rib bays if the sheeting is flexed by say picking the model up. Once the split has started it will grow as the wing flexes.
My preferred choice is 0.6mm ply. Most people do not know that this thickness even exists but it is readily available from companies such as SLEC. It is much stronger than 0.4mm with no tendency to split and much lighter than 0.8 (0.95mm). It is also much easier to apply to curved surfaces as it is more flexible than thicker ply.

AEB

Re: 1/4 Scale Salto

Posted: 28 Jul 2020, 09:48
by roo Hawkins
Hi Peter all looking good. I have just taken delivery of the salto plug fuz so will be starting a build as well. But I am cutting blue foam wings with carbon spars. But will not be doing a build thread this time.
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Re: 1/4 Scale Salto

Posted: 28 Jul 2020, 11:25
by Peter Balcombe
Ah, you got the modified original :)
I will be very interested to see how yours turns out, particularly with regard to weight & ease of build.
What type of brake are you intending to use?

Re: 1/4 Scale Salto

Posted: 28 Jul 2020, 12:08
by roo Hawkins
Hi Peter I am planning to do brakes like the full size. .I have already cut the wings today out of blue foam but have not decided on the spar yet. I am planning on not trying to make it to heavy so I can take to some of the smaller slopes near to me. I was planning on using round joiners but I have some flat joiner around so may use some of that if I think it will be to heavy. A mate has a 1/3 salto with a single flat joiner and that flys around ok with no problems and is in rcme this month.

Re: 1/4 Scale Salto

Posted: 30 Jul 2020, 14:46
by Peter Balcombe
Carbon joiner & forward incidence peg tubes fitted (4mm carbon rod joiner & peg) and support added prior to fitting the top sheeting.
Staggered main joiner locations can be seen in the pic.

Meanwhile, additional brake blade end ribs have been added to the 1st wing & brake blade lower surface seats extended to each end of each blade, plus extra rib doublers added each side of the taper break rib. (Pic to follow).
The current plan is to fit a short section of upper wing skin between the TE and rear Aux. spar so that the upper part of the brake blades can be partially released prior to installing similar partial rear skin on the bottom.
The idea is to try to ensure that the brake blade profiles match the adjoining wing surface, but can still be released easily for final tidying etc. prior to hinging & servo drive installation.
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Re: 1/4 Scale Salto

Posted: 31 Jul 2020, 17:49
by Peter Balcombe
Forgot to take a photo of the extra brake end riblets before moving on, but covered in photos below.
A section of top skin has been fitted up to halfway across the rear aux. spar & brake cut line marked onto this.
(I probably could of fitted the complete top skin, or at least the inner section, but wanted to keep the brake servo area clear until I am confident that the brake removal & hinging method will work on this first build).
Once the skin glue has fully set, I will confirm upper cut lines are correct by using a small drill bit pushed through from below at the corners before releasing the brake end riblets at the front of each blade. In reality, I can probably completely remove the brake structures at this point & skin the lower sections separately.

Meanwhile, the 1st tailplane half has had it’s top skin fitted & a thin-wing servo tried for size. A similar fitting technique could be used for other servo types as long as the thickness is not more than 11mm in order to keep the servo casing under the bottom skin.
Brake end riblets
Brake end riblets
Brake upper edges?
Brake upper edges?
Tailplane servo location
Tailplane servo location

Re: 1/4 Scale Salto

Posted: 03 Aug 2020, 12:04
by Peter Balcombe
With the rear section of lower skin in place (after carefully masking off the lower blade contact area with the internal support) the blades have now been carefully removed.
In retrospect, the blades could have done with some internal support at their upper LE before skinning, but this can easily be added now they have been released.
The photos below show the freshly released blades. The yellow bands are the thin glossy finish tape used as a release layer for the lower front section of each blade.
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Re: 1/4 Scale Salto

Posted: 06 Aug 2020, 12:20
by Peter Balcombe
A bit more progress on the tail feathers with the LE strip added & control surfaces plus tip blocks tack glued to the forward sections so that everything can be sanded to profile.
I’ve also decided to fit 9g MG servos instead of the drawn 21g thin wing mini types to save weight at the back end. Thus the internal servo mount plate has been modified slightly & the hatch size reduced. (Hatch aperture to be cut out once lower skin patch glue has set).
I still need to make servo a connector slot at each root, but the next job will be to separate the (aerodynamic balance) tip sections prior to removing the control surfaces again in order to bevel the LE.
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Re: 1/4 Scale Salto

Posted: 08 Aug 2020, 10:58
by Peter Balcombe
Tailplane halves now have tips sorted & edges faced with 0.4mm ply.
Servo box aperture resized for the smaller size servo, ready to have some small internal location blocks fitted & connector aperture made in the root.
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Meanwhile brake assembly hinging has started on the 1st wing. Inner blade dry fitted & checked for free movement.
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Outer brake has also now been hinged, so time to look at servo linkage to the inner blade which will be hard linked to the outer blade via the central pivot tube.

Re: 1/4 Scale Salto

Posted: 09 Aug 2020, 12:21
by Peter Balcombe
Tailplane joiners now installed in the fuselage (using a small liteply plate at the end of each tube to help anchor it to the fuselage), plus holes drilled for front incidence pegs, so trial installation done.

Brake servo connection also done & operation checked. Hopefully, the operation is just as good when both blades are linked together.
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Re: 1/4 Scale Salto

Posted: 09 Aug 2020, 13:51
by Peter Balcombe
Short video attached showing the inner Brake blade operation.
Note that the clamps are there to hold the pivot tubes in place until I am confident enough to break out the epoxy ;)

With brake operation accomplished, I can complete the wing skinning.


Re: 1/4 Scale Salto

Posted: 09 Aug 2020, 17:50
by roo Hawkins
Looking good Peter. I have just made the brakes for my salto but mine are hinged with glass tape but looks the same as your. Will have to post pictures.

Re: 1/4 Scale Salto

Posted: 10 Aug 2020, 14:36
by roo Hawkins
Pictures of my build
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Re: 1/4 Scale Salto

Posted: 15 Aug 2020, 11:10
by Peter Balcombe
1st wing now has top skin fitted & turned over to fit lower skin false LE balsa strip support and servo hatch support.
Bearing in mind previous comment about thin ply skins, I will cut some foam inserts for the inner panel D box to help avoid handling damage, but having already fitted the upper skins, I will cut these using the 2nd wing structure as a template.

Meanwhile, the tailplane attachment has been completed, including cutting slots for the servo connector holders. The tailplanes slide over the plugged in connectors as they slide home.
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Re: 1/4 Scale Salto

Posted: 16 Aug 2020, 09:11
by VinceC
Interesting photo I came across today
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Re: 1/4 Scale Salto

Posted: 17 Aug 2020, 20:02
by Peter Balcombe
The 2nd wing structure went together quickly once the main spars had been spliced & tapered.
I happened to pick up a large piece of packaging polystyrene whilst at the local recycling centre earlier today, so have now cut small blocks to fit the inner panel D box spaces on both wings & profiled using a Hotwire bow.
The idea is that these foam blocks will help support the thin ply skins to prevent finger damage during rigging etc.

The 1st wing lower skins can now be fitted once the servo cables have been threaded though the pre-cut holes in each rib. The wing joiner box can be made up for the 2nd wing - remembering to fit this so that the 4 joiners are interleaved in the fuselage :)
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Re: 1/4 Scale Salto

Posted: 20 Aug 2020, 12:45
by Peter Balcombe
Bottom skins fitted to the 1st wing yesterday & servo hatch openings found today.
I have also cut down a length of stock TE section to size & tack glued to the hinge spar ready for shaping to profile.
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Re: 1/4 Scale Salto

Posted: 21 Aug 2020, 14:26
by Mike F
Hi Peter

Nice to see the Salto modelled with authentic trailing edge brakes. The Valenta version has full length flaps.

Mike

Re: 1/4 Scale Salto

Posted: 24 Aug 2020, 22:07
by Peter Balcombe
Thanks Mike,
Yes, the TE brakes look good, although time will tell how well the thin down-going blades survive landings if not retracted before touchdown.
The built up structure (with full length 1/16” ply ribs at the brake ends + full chord ply skins gives the small central TE section between the brakes) gives a reasonable amount of support & keys the brake hinge areas into the wing structure nicely.

The 1st wing now has its hardwood LE & tip block added and is nearly ready for glassing. (Just need to cut out the aileron, finish profiling the LE & tip block).
The 2nd wing is progressing rather quicker than the first with the experience gained in the brake blade area. The blades are now ready to be released from the inboard section tomorrow, prior to checking pivots/actuation before completing the wing skinning.

Meanwhile, I have drawn up the fuselage joiner assembly (now that I can physically measure wing root separation on a fuselage) & can get the ply scissors box parts cut shortly. As with my recent PIK20 thread, I will make up the joiner box assembly & then fix this into the fuselage.

Photos on the above progress to follow tomorrow.

Re: 1/4 Scale Salto

Posted: 25 Aug 2020, 11:25
by Peter Balcombe
2nd wing brake blades released this morning, plus aileron released on the 1st wing.
Now some tidying up to do, plus facing the aileron ends, bevelling LE & fitting horn.
Wing root layout also taped to the fuselage root stub to confirm match & spot through joiner, incidence pin, wing retention & servo connector locations.
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Re: 1/4 Scale Salto

Posted: 03 Sep 2020, 17:35
by Peter Balcombe
Steady progress over the last week or two to get the 2nd wing more or less to same state as the 1st.
Ailerons are having end capping fitted & ready for fitting horns.

Meanwhile, attention has turned to the fuselage.
The wheel opening has been released ready to fit the 3.5” wheel identified on the original PT build instruction sheet.
However, a Dubro 3.5” wheel is a bit neat in the width department, so a 3.25” may be a better choice unless a slightly narrower wheel is used.

The fuselage wing root stub has also been marked (using root section drawing template) for wing retention peg centre, wing joiner & MPX servo connector apertures, plus rear incidence pin centre.
The cockpit coaming has been traced & a card canopy frame template used to cut a 0.8mm ply canopy frame base plate which has the rear section (behind pilot seat) blanked off as usually done on the full size - covers wing joiner/control connections.
After fitting a glossy release tape on the cockpit coaming & carefully protecting the fuselage from spills/drips, the canopy frame base has been epoxied to a couple of layers of glass cloth to hopefully form a nicely shaped base for the canopy frame.
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Re: 1/4 Scale Salto

Posted: 05 Sep 2020, 17:14
by Peter Balcombe
The canopy frame base shown last time has been cleaned up and then 2 layers of 2mm Liteply added around the edge to build up a canopy glueing land. This will probably be attached to the fuselage using a front peg & rear magnets.

As the fuselage cockpit framing was some 18mm wide, the front part has been cut back to 10mm to match the canopy frame width. A couple of strips of carbon roving has been added along the top of the fuselage side, just under each coaming & covered by glass tape to reinforce the area as a result.

After looking at a few full size Salto photos, I have decided to reduce the wheel diameter from 3.5” to 3”. A Dubro wheel has been fitted in a simple wheel housing (two 3.5” Dia. semicircles & 0.8mm ply surround). The housing will be located from the inside of the fuselage wheel opening & glassed in position.
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Re: 1/4 Scale Salto

Posted: 05 Sep 2020, 21:07
by terry white
Peter, an excellent build thread showing your excellent work as usual.

Re: 1/4 Scale Salto

Posted: 05 Sep 2020, 21:38
by Peter Balcombe
Many thanks Terry
I’m collecting some laser cut fuselage wing joiner box parts tomorrow morning, so hope to be able to do an initial assembly in a couple of days.

Re: 1/4 Scale Salto

Posted: 07 Sep 2020, 15:41
by Peter Balcombe
The wheel box was tack glued into position (using Polyester resin), then the small gaps filled using small pieces of 0.8mm ply before sealing all around with thickened (micro balloons) resin. The wheel box installation is now ready for reinforcing with glass in due course.

With the fuselage joiner assembly parts now to hand, these have been dry assembled (using M3 bolts through the four pre-cut holes in all parts) and the ends fettled to fit the internal fuselage profile prior to joining all parts except the rear plate with epoxy. (Don’t use too much epoxy as you will otherwise have a job cleaning out the joiner tube slots!)
A 1/4” thick fuselage bulkhead is provided & this can be used at the rear of the joiner assembly to firmly anchor it to the fuselage and act as a wing spreader bar. The bulkhead also sits just behind the wheel, so helps spread landing loads into the fuselage structure

With the joiner assembly positioned, the 4 bolt holes can be spotted through to the bulkhead & holes subsequently drilled. (I made the bulkhead holes 4mm to allow some adjustment during final fitting to ensure the wing joiners were correctly positioned in the wing roots). I’ve currently only enough joiner tube in stock to fit 1 joiner per wing, so will delay final fixing when Gliders Distribution can re-stock.
However, I hope to be able to do a trial wing assembly when the weather improves - hopefully tomorrow.
Wheel box sealed
Wheel box sealed
Wheel fitted
Wheel fitted
Joiner assembly
Joiner assembly
Joiner & bulkhead
Joiner & bulkhead

Re: 1/4 Scale Salto

Posted: 08 Sep 2020, 10:17
by Peter Balcombe
1st assembly just done & everything seems to fit :)
The cavalry are arriving soon with more wing joiner, so will be able to set all into place & then get an idea of amount of weight needed up front to achieve balance in order to cast a nose weight compatible with a nose release.
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Re: 1/4 Scale Salto

Posted: 08 Sep 2020, 17:33
by B Sharp
Peter, I've never seen the wing joiner system done like that before. I must bear it in mind if I use steel blades again in the future.
Brian. :)

Re: 1/4 Scale Salto

Posted: 10 Sep 2020, 23:56
by Cliff Evans
Looking good Peter.

Re: 1/4 Scale Salto

Posted: 20 Sep 2020, 15:44
by Peter Balcombe
Canopy frame fitted with fixings comprising a 3mm Carbon peg at the front & 3 magnets at the rear.
Now ready to be painted prior to fitting the canopy.

Meanwhile, a moulded nose weight has been cast and a tow release installed. As usual, the nose weight will be fixed in place using silicone sealant - makes subsequent removal pretty easy ;)
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Re: 1/4 Scale Salto

Posted: 25 Sep 2020, 10:45
by Peter Balcombe
Canopy frame now painted & ready for canopy fixing.
Meanwhile, the nose weight/tow release has been fitted and the release servo installed on a Liteply plate, in addition to a further battery mounting plate on the side of the fuselage.

The wing tips have been modified to accept plug-on tips as a variety of tip plates/winglets/smoke canister arrangements can be fitted on the full size gliders.
I have gone for the “fish” type plate which has a skid & small vertical fin.

The upper wing surfaces have been glassed with 25gsm cloth & epoxy resin, so time to mask the airbrake seats & do the underside plus all of the flappy bits.
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Re: 1/4 Scale Salto

Posted: 26 Sep 2020, 22:29
by steve dowell
Hi peter looking very good , I,m on your tail .. I will send you some photos soon.

Re: 1/4 Scale Salto

Posted: 28 Sep 2020, 15:29
by roo Hawkins
Looking good Peter. I need to re start my salto soon.

Re: 1/4 Scale Salto

Posted: 30 Sep 2020, 09:10
by SteveArchibald
Wow that's coming along beautifully.

I better get building.

Re: 1/4 Scale Salto

Posted: 30 Sep 2020, 11:23
by Peter Balcombe
With the wing surfaces now glassed, it is time to mask off around the underside brake apertures and the brake seat using a shiny surfaced tape which will have release agent applied.
The brake vanes will be held in place whilst glassing resin cures in order to ensure the vane surface conforms to the rest of the wing as far as possible.
Once this is done the vanes can be released and the top rear surfaces glassed unsupported.
Ailerons & servo hatches can also be glassed whilst I have resin mixed.
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Re: 1/4 Scale Salto

Posted: 30 Sep 2020, 17:53
by Peter Balcombe
Brake vanes glassed & temporarily covered with polythene sheet to allow them to be clipped at rear & weighted at front whilst the resin cures overnight. Top surfaces of ailerons & servo cover plates also done at same time.
Hopefully, the parts release ok, then the remaining sides of the brake vanes & ailerons can be done to complete the exercise.
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Re: 1/4 Scale Salto

Posted: 18 Oct 2020, 18:17
by Peter Balcombe
With the wing now glassed & rubbed down with 240 grit wet&dry (used wet), it’s time to bite the bullet and install the TE brake blades :?
The inside of the blades and wing blade seat were first given a coat of Acrylic Appliance White Gloss from a rattle can, as these areas may be a bit more difficult to get to for painting once the blades are in place.

The RH wing blades pivot slots were then cleaned up and one of the blade pivot tubes (both ends on centre one) fixed to the axle. (The blades are linked to each other via the centre pivot, so make sure that the central tube of the 3, which is fixed in the wing, rotates wrt the outer tubes which are fixed in the blades).

I installed the brakes in 2 steps:
1) With the blades securely taped/clamped in place (without servo pushrod connected) the pivot assemblies can be carefully epoxied into the blades only. I clamped a small piece of plastic sheet over each joint to ensure that the pivot tubes didn’t protrude above the brake upper surface. Once the epoxy has cured, the linked blades should be able to be rotated & lifted clear of the wing to check all ok & the wing pivot tubes still rotate on the axle.

2) Now fit the servo pushrod and reinstall the blade assembly in order to epoxy the wing pivot tubes. Check all is well and the pushrod operates ok, then carefully epoxy the wing tubes in place making sure that the epoxy doesn’t get to the axle anywhere. I used plastic sheet strips again to stop the tubes protruding above the wing skin.
I had to release the outer end pivot :oops:

Hopefully, once the epoxy is dry, the blades rotate cleanly and can be fully opened & closed using the servo pushrod.
Servo operation to be tried next ....
RH brake parts
RH brake parts
Blade pivots being glued
Blade pivots being glued
Linked blades
Linked blades
Installed blades closed
Installed blades closed
Installed blades open
Installed blades open

Re: 1/4 Scale Salto

Posted: 19 Oct 2020, 16:59
by Cliff Evans
Salto brake operation.


Re: 1/4 Scale Salto

Posted: 19 Oct 2020, 19:49
by steve dowell
Peter very nice work

Re: 1/4 Scale Salto

Posted: 21 Oct 2020, 11:05
by Peter Balcombe
Tailplane halves now covered with film & control surfaces hinged using small pin hinges.
Servo leads shortened by 60mm to allow enough to be poked out for connection, but short enough for this to retract back into the tailplane as it is pushed home on its carbon joiner/peg.
The servo is fixed using hot glue & very short pushrods made using 2mm threaded rod.

All seems to work ok when installed & servos driven from Rx end of the extension leads :)
F018C909-9664-4EB6-8669-597E5043E777.jpeg
C7FDC473-97A9-4201-BB17-1D71F1F50DA6.jpeg


Re: 1/4 Scale Salto

Posted: 23 Oct 2020, 17:17
by Peter Balcombe
I have been finishing off all the last jobs on this build apart from wing painting over the past week.
Brake vane pivot slots now filled & sanded flush with rest of the wing/blades.
Ailerons dry fitted & pushrods made up.
Tail cone made from balsa & given an initial coat of Acrylic to seal.
A shaped seat has been made by laminating 4-5 layers of glass cloth between plastic sheets and curing in a Hotwire cut shaped foam former. The cured cloth has been cut to shape and epoxied to a couple of 1/8 balsa sheet stand-offs which will now be fixed into the fuselage. The result puts the pilot figure at about the correct position & the canopy fits - which is always a bonus :D
Over to Cliff now, for the paint shop & radio installation.
Tail cone
Tail cone
Brake underside
Brake underside
Aileron installation
Aileron installation
Moulded seat
Moulded seat
Seat painted
Seat painted
Pilot fits
Pilot fits

Re: 1/4 Scale Salto

Posted: 23 Oct 2020, 22:06
by Max Wright
The excitement builds, Peter. 8-)

Re: 1/4 Scale Salto

Posted: 03 Mar 2021, 18:39
by fastjetflyer21+
Hi Peter. I have been reading your review of the build of your great looking Salto. One question springs to mind - how have you locked the tail plane halves together in the fuze?

Re: 1/4 Scale Salto

Posted: 03 Mar 2021, 19:04
by Peter Balcombe
The tailplane halves are attached using a carbon rod into a tube in the Fuz, plus an alignment peg at front.
My post on 9th Aug last year shows a shot of the 2 crossed fuselage tubes.
There is no locking device, similar to many AMT setups, relying on the joiner tube friction (maybe assisted by a spot of pritt-stick glue or similar) to resist any tendency to inadvertently slide out in flight.

Re: 1/4 Scale Salto

Posted: 03 Mar 2021, 23:03
by Cliff Evans
Tape the joint on the underside works well.

Re: 1/4 Scale Salto

Posted: 04 Mar 2021, 09:16
by roo Hawkins
Mine has a cup hook in each tail plane with a elastic band between the two going through the fuselage.

Re: 1/4 Scale Salto

Posted: 26 Mar 2021, 22:58
by mjcp
Peter Balcombe wrote: 13 Jul 2020, 12:08 With the outstanding lower rear spar inserted to complete the basic framework, attention turns to the joiner assembly.
This is made up using interleaved brass tubes and 3mm spacers, epoxied together to form a solid block as shown.
Note that the joiner assembly needs to be cleaned up to reduce its overall thickness to that of the joiner tubes (16mm) as it will be a very neat fit between the spars at the outer end, so any thicker & the upper spar will not sit down correctly.
Any thoughts on a 1.5mm bar instead of the 2mm ? (with corresponding thinner box, yes, there would need to be some packing adjustment)

Gliders are out of stock of 15x2 / 16mm box, but I've located some 15x1.5 / 16mm box ...

(I note my Pik 20 uses a single 15mm bar with its wider wings!)

M

Re: 1/4 Scale Salto

Posted: 27 Mar 2021, 08:58
by Peter Balcombe
Marc,
I would think that if the material is a similar carbon steel, then 2 x 1.5mm blades would probably be ok as I think the 2 x 2mm are possibly a bit of overkill.
I used twin blades & what I hope is a strong wing to stand up to the spirited aerobatic manoeuvres that a Salto might be put through.

I would think it best to put any spacer between the 2 blades to make the joiner area the same width as I think this will help structurally.

Maybe any ex-structural engineers may like to comment?

Re: 1/4 Scale Salto

Posted: 27 Mar 2021, 12:16
by mjcp
It’s the same box and bar as the gliders stuff.. just this is in stock!

Re: 1/4 Scale Salto

Posted: 29 Mar 2021, 09:20
by mjcp
Peter Balcombe wrote: 27 Mar 2021, 08:58
Thanks for your previous answers Peter!

Another day... another question!

Did you stick with 0.4mm ply and glass or did you go with the suggestion of 0.6mm or the drawn 0.8mm sheeting for the wings?

Did you add any carbon to the spar ?

TIA!
Marc

Re: 1/4 Scale Salto

Posted: 29 Mar 2021, 10:10
by chris williams
mjcp wrote: 27 Mar 2021, 12:16 It’s the same box and bar as the gliders stuff.. just this is in stock!

Where did you get it, Marc...?

Re: 1/4 Scale Salto

Posted: 29 Mar 2021, 10:31
by mjcp
chris williams wrote: 29 Mar 2021, 10:10
mjcp wrote: 27 Mar 2021, 12:16 It’s the same box and bar as the gliders stuff.. just this is in stock!

Where did you get it, Marc...?

Price gouged* on FleaBay:
https://www.ebay.co.uk/itm/Brass-Steel- ... 3929524616


*Ok, not gouged, but more expensive.... Gliders: £18 + shipping, but out of stock, Seller above, £28 shipped.

Marc

Re: 1/4 Scale Salto

Posted: 29 Mar 2021, 11:24
by chris williams
Crikey... (or words to that effect)

Re: 1/4 Scale Salto

Posted: 29 Mar 2021, 11:34
by Cliff Evans
mjcp wrote: 29 Mar 2021, 10:31
chris williams wrote: 29 Mar 2021, 10:10
mjcp wrote: 27 Mar 2021, 12:16 It’s the same box and bar as the gliders stuff.. just this is in stock!

Where did you get it, Marc...?

Price gouged* on FleaBay:
https://www.ebay.co.uk/itm/Brass-Steel- ... 3929524616


*Ok, not gouged, but more expensive.... Gliders: £18 + shipping, but out of stock, Seller above, £28 shipped.

Marc
I think you will find that this is Gliders Ebay shop, both in Newark! If so, bit of a price hike!!

Re: 1/4 Scale Salto

Posted: 29 Mar 2021, 11:41
by Cliff Evans
This is GlidresUK!

Screenshot(2).png


Ebay seller details:


Screenshot(3).png

Re: 1/4 Scale Salto

Posted: 29 Mar 2021, 22:01
by mjcp
I started my build with the tail plane, the idea being I can get my eye in and if I lunch it, a recut would be less of a bent to the wallet than a set of wing ribs and skin!

Stb ruddervator 1st off the plan, followed by the Port one. Eye mostly in.
IMG_1924.jpeg

Bit of doubling ready for the hinges - This was my 1st moment of insecurity: allowing for the skin, the LE and TE were still higher than where the skin would end up. Eventually I worked up the courage to assume it would need to be sanded back to profile, hence the doublers look way taller than needed in the pic.
IMG_1927.jpeg

Skinning was a non event, but the next step had its own set of nerves. The TE is a combination of stock TE and additional stock to fill in a narrow wedge as the chord increases towards the fuse / root. In the end, some odd bin stock was glued and with the aid of some packing tape (to protect the TE that didn't yet need adjustment) and a (Messrs. Heath, Robinson patented) flat sanding sheet did the job.
IMG_1932.jpeg
IMG_1933.jpeg

A quick trace of the plan, cut to a template and then attacked with the bandsaw resulted in the desired plan form control surface. This was marked and then fettled with a block plane borrowed from the other side of the workshop to get the root to tip taper correct, with suitable graduation along the profile.

Meanwhile the balance tabs were formed from two cross grain thicker balsa sheet offcuts. (Looks like the LE had seen some profile work by this point too!) The tabs were rebated to match the bevelled profile of the TE and to offer a larger surface area for the joint.
IMG_1934.jpeg

Next up, the balance tabs* were blended to the control surface / TE profile in the same packing tape masked / sanded way. Then the LE / body of the tab was profiled to match its ruddervator. (Here's a before and after)
IMG_1937.jpeg

1st side done, boundary between the ruddervator and the balance tab was faced with 0.4mm ply
IMG_1935.jpeg

And its pair.
IMG_1940.jpeg

Hand aligned, I'm happy with the two faces, they will be straight and close by the time the hinges get involved.
IMG_1942.jpeg

A pair of ruddervators.
IMG_1943.jpeg

The servo hatches have also been cut on the rear. Servos will be HiTech HS-125MGs all round unless anyone else has any thoughts?

*Balance tabs - not sure what the name of the bit ahead of the hinge is called on a "horn balanced" surface (I've never heard it called a horn!) and balance tabs tend to be on the TE...

n.b. happy to shift to a sep. thread to avoid hijack if the powers that be prefer?

Marc.

Re: 1/4 Scale Salto

Posted: 30 Mar 2021, 00:30
by Cliff Evans
Looks good Marc.

Re: 1/4 Scale Salto

Posted: 29 May 2021, 16:25
by Cliff Evans
The new Pat Teakle Salto flew today for the first time. New wing section HQW 2.5/12. Flew faultlessly off of the tow, just needed to calm the surfaces down a bit but yes, a great success.

20210529_160132.jpg

Re: 1/4 Scale Salto

Posted: 30 May 2021, 10:58
by Mike F
Hi Marc

Great to hear that the Salto has flown. Love the training edge brakes.

Mike

Re: 1/4 Scale Salto

Posted: 30 May 2021, 13:45
by Cliff Evans
Mike F wrote: 30 May 2021, 10:58 Hi Marc

Great to hear that the Salto has flown. Love the training edge brakes.

Mike
Its Cliff, not Marc!

Re: 1/4 Scale Salto

Posted: 30 May 2021, 20:29
by roo Hawkins
I cliff well done with the maiden .just need to fly mine. Will be off the slope.

Re: 1/4 Scale Salto**

Posted: 25 Nov 2022, 20:00
by andynrose315
i could not resist purchasing a short kit and now starting the build following Peters journey. the one thing i am not sure about is the scale flaps which i have never built before. its a friday and im struggling to see the best way to build them; at the moment i think its - construct wing; bevel and add the doubler(?) add top ply skin, mark outline of flaps; add balsa between ribs; add tape or similar to act as release, add bottom ply skin partial only. then cut and release.

Re: 1/4 Scale Salto**

Posted: 26 Nov 2022, 09:44
by Cliff Evans
andynrose315 wrote: 25 Nov 2022, 20:00 i could not resist purchasing a short kit and now starting the build following Peters journey. the one thing i am not sure about is the scale flaps which i have never built before. its a friday and im struggling to see the best way to build them; at the moment i think its - construct wing; bevel and add the doubler(?) add top ply skin, mark outline of flaps; add balsa between ribs; add tape or similar to act as release, add bottom ply skin partial only. then cut and release.
Sounds like a plan! How long is a piece of string? Everyone will do it in their own chosen way.

Re: 1/4 Scale Salto**

Posted: 30 Nov 2022, 13:11
by andynrose315
afternoon - i have one wing panel on the way, and just looking at what is recommended for the number of ribs to remove for the wing joiner. think the plan suggests R1 to R3 inclusive removed with a ply doubler on R4.

Re: 1/4 Scale Salto**

Posted: 30 Nov 2022, 16:05
by Cliff Evans
It is not the ribs that are removed, it is the section shown that is removed to place the joiner box in.


section to remove after construction of wing for placement of joiner box before sheeting
section to remove after construction of wing for placement of joiner box before sheeting
section in black to be removed after construction for wing joiner box.
section in black to be removed after construction for wing joiner box.

Re: 1/4 Scale Salto**

Posted: 03 Dec 2022, 12:43
by andynrose315
Cliff thanks. okay so involves removing those areas including r4. was not sure if joiner stopped just before it or not. and no intention of taking the ribs out. :D

Re: 1/4 Scale Salto**

Posted: 03 Dec 2022, 17:58
by Cliff Evans
joiner stops in R4 and cap the end with 1.6mm ply.

Re: 1/4 Scale Salto**

Posted: 24 Jan 2023, 08:09
by andynrose315
first wing is progressing well and been sheeted. i have gone with 0,6 mm ply rather than the 0.4 in the thread. the ailerons are top hinged. with previous smaller models i have taped the hinge or used covering. any suggestions for this model?

Re: 1/4 Scale Salto**

Posted: 24 Jan 2023, 09:07
by Cliff Evans
A tape hinge will be fine.

Re: 1/4 Scale Salto**

Posted: 22 Feb 2023, 18:06
by Peter Balcombe
Only reason I didn’t use 0.6mm ply on the prototype buiId was the slight extra weight & thought of cutting flaps free with the thicker material. ;)

Re: 1/4 Scale Salto**

Posted: 15 Mar 2023, 13:25
by andynrose315
thanks Peter. i hope you are recovering well. looking for guidance on how best to finish the wings once glassed. is there a recommended paint to use? i have had limited success with spay painting but that may reflect i rarely spray paint.

Re: 1/4 Scale Salto**

Posted: 20 Mar 2023, 09:55
by Peter Balcombe
Andy, I seem to remember giving the model to Cliff with unpainted wings, so I expect he used rattle can primer/ filler, then rattle can top coat. Perhaps Cliff can correct/ elaborate if he spots this post :D
I’m slowly recovering, but I guess in reality,it’s likely to be around the end of the year beforeI’m recovered as far as I’m likely to be😏

Re: 1/4 Scale Salto**

Posted: 20 Mar 2023, 12:57
by Cliff Evans
Peter's memory serves him well, rattle cans it was!

Re: 1/4 Scale Salto**

Posted: 14 Apr 2023, 16:09
by andynrose315
Peter thanks. sorry this is probably a very New Member question. if i were to spray paint the fuselage can this be done directly over the white finish?

Re: 1/4 Scale Salto**

Posted: 14 Apr 2023, 20:17
by Cliff Evans
andynrose315 wrote: 14 Apr 2023, 16:09 Peter thanks. sorry this is probably a very new member question. if i were to spray paint the fuselage can this be done directly over the white finish?
Yes, you can but you will need to flatten it down with 40 wet and dry "wet" to give the gel coat a key.

Re: 1/4 Scale Salto**

Posted: 14 Apr 2023, 21:55
by geoff_crew
Cliff,do you mean 400 wet and dry?
Geoff

Re: 1/4 Scale Salto**

Posted: 14 Apr 2023, 23:12
by Cliff Evans
geoff_crew wrote: 14 Apr 2023, 21:55 Cliff,do you mean 400 wet and dry?
Geoff
Yes, damned fingers!!!

Re: 1/4 Scale Salto**

Posted: 17 Apr 2023, 20:19
by andynrose315
run into a little problem with the glass fibre over the wing. applied a light cloth and spread thin coat of epoxy resin careful with the proportions of resin hardener etc and not to apply too much or lift the cloth. in patches the resin remains tacky after best part of a week. i think it is a result of temperature being too low so moved the wing into a warmer area. looking for help on best way to proceed. i have read on rcgroups various threads to remove tacky areas by sanding. some appear to have applied another coat or use acetone. before making a mess thought i would ask and see recommendations of others.

Re: 1/4 Scale Salto**

Posted: 17 Apr 2023, 22:48
by Cliff Evans
You can try using Talcum powder! I had a similar problem with a paint that remained tacky. I searched the web and found that someone had recommended using talcum powder to help dry the paint off, and it worked. Not sure what it will be like on resin. I will ask John Hall, he is the expert on resins.

Re: 1/4 Scale Salto**

Posted: 17 Apr 2023, 23:29
by fibreglassjohn
Quite possibly a result of poor initial cure due to the low temperature....how low was it? If prolonged poor initial cure this can prevent ever getting a full cure. I would place the wing at 25°c for 24 hours and then reassess. If still tacky, I would recommend carefully wiping with acetone on a rag (not tissue) sanding will probably make a sticky mess and compromise the integrity of the glass fabric.
I believe this is glass/epoxy over thin ply? If so was the ply surface sanded to remove the release agent used during its manufacture? this could inhibit curing . What kind of epoxy was used? some do not work well in thin layers or as coatings.

Re: 1/4 Scale Salto**

Posted: 18 Apr 2023, 08:04
by andynrose315
so it is glass over ply and the ply was lightly sanded beforehand. i have been using easycomposits laminating resin. i’m guessing but the temperature likely to have been 15 degrees and this would have been for several days as i was away from home. i will keep in a warm place and see if it improves. the resin was a new purchase. the residual that was left in the pot has cured ok and not tacky in the surface.

Re: 1/4 Scale Salto**

Posted: 19 Apr 2023, 18:18
by Peter Balcombe
I have sometimes found that the EL2 resin cures with a tacky surface despite having been weighed out accurately &/wel mixed,then cured in temperatures above 18 C.

Leaving the item for a while in as warm room seems to improve the cure, but not necessarily make it go completely hard!
Peter

Re: 1/4 Scale Salto**

Posted: 21 Apr 2023, 07:50
by andynrose315
left in a warm room for several days and tackiness has reduced and gone in most places. a few small areas i used a little acetone and all seems ok.

Is there a resin that is recommended for this type of application as from Peters comments this may be EL related. Last thing i want to do is repeat for the other side and wing.


thanks for the responses above

Re: 1/4 Scale Salto**

Posted: 21 Apr 2023, 09:51
by Cliff Evans
I have always found that the West system is very reliable.
https://www.ebay.co.uk/sch/i.html?_nkw= ... xEQAvD_BwE

Re: 1/4 Scale Salto**

Posted: 19 Jul 2023, 07:01
by Robcrad
Quick question for you Cliff,
What are the control throws are you using for the salto?

Regards
Rob

Re: 1/4 Scale Salto**

Posted: 19 Jul 2023, 16:49
by Cliff Evans
Sorry Rob, I can't remember, moved it on a while ago now.

Re: 1/4 Scale Salto**

Posted: 19 Jul 2023, 17:21
by Barry_Cole
Look in your flight log book, it's bound to be in there.

:lol: :lol: :lol: :lol:

BC

Re: 1/4 Scale Salto**

Posted: 21 Jul 2023, 14:47
by Peter Balcombe
I seem to think that it has been through 2 owners since Cliff moved it on.
Cheers,
Peter

Re: 1/4 Scale Salto**

Posted: 05 Jan 2024, 13:13
by andynrose315
Happy new year all. pls can someone confirm the CoG for the salto. did a quick calc and it appears to be around 87mm. was not sure if the value on the leaflet is for a larger span. thanks.

Re: 1/4 Scale Salto**

Posted: 06 Jan 2024, 12:38
by Mike F
Hi
I think that 87-89mm is about right. My Valenta Salto at 4.5m wing span is at 93mm.
Salto CofG.jpg

Re: 1/4 Scale Salto**

Posted: 06 Jan 2024, 12:41
by sp250
I don't know the CG on the PT one (sold mine a few years ago), but the similar sized Baudis one (4060mm span, 260mm root chord) flew well at 85mm and 83mm when fully ballasted with extra 2kg and on low rates.
John M

Re: 1/4 Scale Salto**

Posted: 06 Jan 2024, 18:39
by Cliff Evans
89mm is a good starting point.


Brochure Salto.pdf
(2.36 MiB) Downloaded 62 times

Re: 1/4 Scale Salto**

Posted: 10 Jan 2024, 20:59
by andynrose315
thanks all ready to go………