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.

Mick Reeves 1/4 scale RF4

Post by Peter Balcombe » 22 Apr 2015, 21:02

Continuing this build thread from the old forum now that the Olympia build is complete.
Picked up previous build with left wing panel almost completely sheeted and with hobbyking electric airbrake in place.
I have now sheeted the top of the right wing and am about to turn it over to add the aileron sub spars, prior to adding the lower D box sheeting when I have restocked my 3/32 balsa sheet supply.

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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 Apr 2015, 11:10

Whilst awaiting a balsa delivery to complete the wing sheeting, I have made a start on the fuselage, commencing with the right hand side frame.
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For those starting this build, you should be aware that the supplied kit build instructions (at least with my fairly recently purchased kit) refer to an older version of the kit which had foam deckings (and perhaps more pre-cut & numbered parts). I have found it a bit frustrating to try to work out whether numbered parts are actually supplied already cut, or are items needing to be cut from standard sheet/strip material as no material size is given. It is then a matter of searching the drawing to try to find the part & work out what it is. Some of the numbers shown on the drawing refer to a part in the general vicinity, rather than on the part itself & a few more arrows pointing to the actual part would be useful.
Parts 3 & 67 are not shown on the drawing at all & actually refer to an 1/8 balsa sheet piece just forward of item 12, and a 1/4 balsa sheet reinforcement piece around the tailwheel mount respectively.

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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 » 27 Apr 2015, 19:48

More balsa has just arrived.
However, in the meantime I have managed to get both fuselage sides put together and have just started the joining process as shown below.
Next job is to pull the sides in and add the forward formers.
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Peter Balcombe
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Re: Mick Reeves 1/4 scale RF4

Post by Peter Balcombe » 28 Apr 2015, 17:47

The next job from last post was NOT to pull the nose in, as I had to add the wing rear seating plate area (pieces 5, 6 & 7), then add the turtle decks.
As Daniel C said a while ago, piece 6 (rear wing seating plate) has different angles on each side & this needs to be altered to fit. Also, piece 7 is a plain rectangle as supplied & the profile needs to be altered to provide notches in each corner to allow this piece to fit between the two sides as F6 fits onto its rear face.
The instructions then say to add the bottom foam turtle deck - which has now been replaced by balsa formers F6-F10, a 1/4 square balsa spine longeron & 1/16 sheet balsa skins.
I decided to skin the turtle deck in two pieces, one side at a time, joining on the 1/4 square spine.
The photo below shows the right side sheet glued in place with temporary pins & masking tape fixings.
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I hope to add the left side turtle deck sheet tomorrow before I go off flying at the slope.

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Peter Balcombe
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Joined: 18 Mar 2015, 10:13
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Re: Mick Reeves 1/4 scale RF4

Post by Peter Balcombe » 29 Apr 2015, 21:45

Bottom turtle deck sheeting now completed and all formers added ready to fit the upper turtle deck sheeting.
The length of some of the fuselage side cross pieces (e.g. A & B) need to be shortened to get the fuselage side separation correct according to the drawing. It looks as if allowance hasn't been made for the 1/8 doubler thickness each side, so the pieces in this area are 1/4 too long.

I happened to be talking about the RF4 build to an ex-structural engineer in my workshop yesterday evening & he couldn't believe the RF4 wing joining method used. As a result, I will be installing a 12mm steel strip & brass box wing joiner assembly (as used on 1/5 scale glider builds) within the inner 3 panels of each wing in the main spar area. As per normal glider practice, I will make a solid assembly which holds the brass box at the correct dihedral angle when epoxied into the 'tween spar void. To enable this mod to take place, I have carefully removed the ply rear spar webs from the 3 inner bays on the right hand wing.
Next job is to make up the brass box assembly and remove the inter-spar section on the inner ribs to allow this assembly to be slid into place from the root end & epoxied in place.

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Peter Balcombe
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Re: Mick Reeves 1/4 scale RF4

Post by Peter Balcombe » 30 Apr 2015, 19:04

Both wings now prepared for joiner modification plus first box assembly made up & trial fitted to check fit and dihedral.
The inter-spar gap is cleared at the rear 1/4" in the first 3 ribs and 1/4" spacers put into the front part. The brass box assembly is made from one 1/8" hardwood & two 1/16 ply pieces cut to slide into the inter-spar gap when epoxied together as a sandwich with the hardwood in the middle & cut to take a 200mm long x 13 x 3mm section brass box at the correct dihedral angle (worked out as 13.5mm over the 200mm length).
The inter-spar gap is 34mm at W1, reducing to 31mm at W4.
I built up the overall box assembly, then tidied the edges and adjusted as necessary to fit between the existing spars.
The pictures below show the box assembly halfway into the wing, all the way, plus a shot from the wing root.
The box assembly will be epoxied into place and 1/16 ply rear spar webs then epoxied on, thus making a totally solid bond between the joiner and the main spars.
I will make up the 2nd box & confirm that both have exactly the same angle before adding them to the wings.
As I now do not need the dowelled 1/4 ply plate to join the wings at the correct dihedral, I will probably cut this in half and permanently fit one half to each wing, using these only for mounting the pre-joined wings to the fuselage as per the original use.
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Peter Balcombe
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Re: Mick Reeves 1/4 scale RF4

Post by Peter Balcombe » 30 Apr 2015, 20:11

A shot included showing the component parts of the wing joiner box prior to making up the sandwich.
Meanwhile a bit more work has been done on the fuselage. The lower turtle back decking has been completed and the upper turtle deck structure added ready for sheeting. The luggage shelf has also been added between the first 2 upper decking formers.
image.jpg
image.jpg

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Peter Balcombe
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Re: Mick Reeves 1/4 scale RF4

Post by Peter Balcombe » 01 May 2015, 22:38

Both wing joiner box assemblies now epoxied in place and the new rear ply spar webbing plates also epoxied in. Hopefully, I can now pick up the 2nd wing sheeting where I left off & get the lower D box sheet in place tomorrow.
Meanwhile, one of the balsa upper turtle-deck side sheets has been pinned in place after dampening the outer surface. This should retain the curvature when dry, allowing it to be trimmed for top joint edge & glued in place tomorrow.

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Peter Balcombe
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Re: Mick Reeves 1/4 scale RF4

Post by Peter Balcombe » 02 May 2015, 22:52

2nd wing D box sheeting completed and upper turtle-deck also sheeted today.
I will add some photos tomorrow before continuing.

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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 » 03 May 2015, 10:35

Promised picture of the fuselage so far. Top decking complete, tailplane seat pieces just added at rear. Now ready to add wing/retract attachment plate & pull in nose to fit front bulkhead.
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