Mick Reeves 1/4 scale RF4

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Peter Balcombe
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Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: Mick Reeves 1/4 scale RF4

Post by Peter Balcombe » 14 May 2015, 15:31

Wings now able to assembled to fuselage so the dowels have been fitted in the wing attachment plate, this plugged into the fuselage, the wing rear location dowels fitted and then the assembled wing mounted onto the fuselage so that the wings can be epoxied to the wing attachment plate in situ as shown in the photo.
Once the epoxy has cured, the wing assembly + bonded mounting plate will be removed from the fuselage and the plate cut at the wing joint, leaving half a plate & one forward fuselage mounting dowel plus the normal rear location dowel and rear mounting bolt on each wing.
The fin sheeting has now been completed and the rudder assembly built up. The rudder photo shows the rudder post pinned on whilst the glue dries.
By the way, I normally use aliphatic glue for all wood joints as this allows the joints to be easily sanded back as necessary without issues with rubbery joints (white glue) or exposed hard joints (cyano).
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Peter Balcombe
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Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: Mick Reeves 1/4 scale RF4

Post by Peter Balcombe » 17 May 2015, 19:33

Many thanks for the comments Pete,
I hope that I will have got around most of the build issues you mention apart from the balsa fuselage longerons as I used balsa as per the plan!. However, following your comments, I think that I will glass the fuselage in lightweight cloth now, as per my wooden glider fuselage practice.
I am using the Mick reeves retract, electric airbrakes and a spruce wing main spar/ steel joiner system so hopefully will avoid some of the other issues. I am not really expecting much soaring from the RF4 (particularly given my stronger but heavier wing) so will also be building a Milan when a friend finishes his 1/3 & 1/4 scale plans.
Thanks for the tip about the outrigger legs. I will now build in a coil at the top of each leg.
I currently plan to fit a 3548/900 electric motor as recommended by Mick. Hopefully this will be big enough!

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Peter Balcombe
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Location: Clevedon, North Somerset, U.K.

Re: Mick Reeves 1/4 scale RF4

Post by Peter Balcombe » 20 May 2015, 17:45

Wing attachment now completed using M5 Tee nuts mounted in the fuselage. I ended up realigning the rear fuselage attachment plate to put its surface parallel to wing lower surface/wing plate. The fuselage side rails also needed to be chamfered to follow the wing dihedral angle.
Moving on to the retract, this has now been fitted and the retract servo fitted immediately behind the bottom of the firewall.
I mounted the servo on the bottom of lite ply battery mounting plate as shown on the attached photo.
A ball joint on the servo arm drives a 2mm pushrod to the retract actuating arm.
The servo has now been fixed in place in its 6mm frame using silicone sealant after first checking that everything worked ok.
image.jpg

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Peter Balcombe
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Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: Mick Reeves 1/4 scale RF4

Post by Peter Balcombe » 25 May 2015, 16:59

The 3548-900 electric motor mount has been made up from some 9mm ply I happened to have to hand & M3 Tee nuts fitted to take the motor back mount fixings. I used the original 4 firewall holes to screw the mount to the firewall whilst 24hr epoxy provides the primary long term attachment. Note that the motor is fitted with the shaft on the same centreline as for an IC engine.
The photo below also shows the sloping battery shelf fitted in the original tank bay. I plan to fit a divider to separate the flight battery from the radio battery.
With all the primary components now available, I hope to be able to try a dry assembly of everything tomorrow prior to sorting out the fuselage/wing fairings.
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Peter Balcombe
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Location: Clevedon, North Somerset, U.K.

Re: Mick Reeves 1/4 scale RF4

Post by Peter Balcombe » 26 May 2015, 09:56

First overall dry assembly today with tail surfaces temporarily pinned in place to check squareness to wings. All ok.
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Peter Balcombe
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Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: Mick Reeves 1/4 scale RF4

Post by Peter Balcombe » 29 Jun 2015, 19:54

Although no posts for a couple of months since the aerotow season started, I have been making slow progress on this model.
With the retract servo and the wing mounting bolts in place the moulded plastic wing root fillets have been fitted and the forward fuselage underside faired into the wing area. The fuselage floor has also been fitted, together with a rudder/elevator servo tray at the rear of the wing mounting area. Plastic exit tubes have been fitted for closed loop rudder and the elevator pushrod made from a hardwood strip.

I have also had a rethink about the electric power system and decided to play safe by making provision to fit a larger motor/battery combination (5055 motor & 5S Lipo) to provide up to 1500W on tap rather than up to about 700W from the 3548 motor on 4S as recommended. This may be overkill, but I would rather have a little too much power available than too little, especially for a first flight!!
As a result of this, I have modified the motor mount to reduce its length by 6mm, with provision to also mount the cowl 6mm further forward to get the propellor backplate in the correct position with the longer motor. The other modification in this area is to fret out the original firewall between the motor mount in order to allow the longer 5S battery to fit in the original tank area sliding down through the firewall.
Photos to follow when I get home from a short break in Kent.

Col Collyer

Re: Mick Reeves 1/4 scale RF4

Post by Col Collyer » 21 Aug 2015, 12:15

Hi Peter
750 watts on a 14 x 7 prop is about right.
Mine ia a TMRC part kit and came out at about 10lbs. It does nice slow aerobatic, but I have found it hard to land without bouncing. The model has got better as I move te cg foreward.
I think you will like your RF4
Col

spike spencer
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Re: Mick Reeves 1/4 scale RF4

Post by spike spencer » 21 Aug 2015, 13:54

Bouncy landings on RF4 and the Milan are Scale behaviour !
Our Milan syndicate insisted that all landings by non-members were conducted engine-off to avoid prop strikes and great expense. A 'wheeler' landing after the initial flare, fuz level & tailwheel up, was more successful in avoiding the kangaroo effect.

Use Rudder (a lot) and enjoy your RF4. :)
Spike S.

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Peter Balcombe
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Re: Mick Reeves 1/4 scale RF4

Post by Peter Balcombe » 21 Aug 2015, 18:33

Many thanks for the comments chaps.
They have reminded me that I had forgotten to take some photos of the current state of play.
Apologies, but other projects have got in the way ;)

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Peter Balcombe
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Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: Mick Reeves 1/4 scale RF4

Post by Peter Balcombe » 23 Aug 2015, 16:12

A couple of photos below of the fuselage in its current state, with motor and tail control servos fitted, plus wing root fairings etc.
Attachments
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