Build of 1/3rd scale Piper Tripacer

[Peter Siggins]

As this model was built at the beggining of the year I thought a back to front post would be different,so I am posting pics of it finished and flying shots.

IMG_0351.JPG (77.87 KiB) Viewed 16061 times

IMG_0353.JPG (68.29 KiB) Viewed 16061 times

IMG_0352.JPG (24.68 KiB) Viewed 16061 times

This is a 1/3rd scale model with a 55cc twin xyz engine ( never heard of it) 105" span weighs 34lbs and has twin landing lights,flaps and rear opening door.
I'll do some build deatails later after seeing how the pics turn out.

[Peter Siggins]

First flown without cowl to check engine

[Dave Parry]

Hi Peter, it was lovely to see you at Gaydon yesterday, I hope you didn't spend to much Lovely model can't wait for the build thread.

[stuart knowles 1611]

The finished model looks to be a cracker. I look forward to the build thread

[Ken Bones]

I love the older civilian types of AC.
Looking fwd to your article.
Ken

[Peter Siggins]

Thanks Dave Stuart and Ken - i hope i dont dissa point.

With any new build first thing is to study the plan and try and get into the designers methods .The designer for this was Wendell Hostetler who has some different ways of doing things.
Firstly cut a kit of bits - I always cut my own as i think this is a rewarding part of any build.

m_001.jpg (36.65 KiB) Viewed 15912 times

m_002.jpg (41.62 KiB) Viewed 15912 times

The cowl on the plan has a balsa rim stuck to the rear to carry the 1/8th sheeting so none of the sheeting overlapped it.I made it 1/8" smaller so the sheeting overlapped to add much more strength.

m_003.jpg (25.84 KiB) Viewed 15912 times

I'll have to look at this to see if the pics are lining up.I thought i'd start building with the fuselage as this doesnt look too clear on the plan.Tyhe sides are 1/4"balsa the full length of the fuselage with 1/4" x 3/8" spruce put in to make the top wing mounts and door frames,The whole side is then covered with 1/8" sheet .Then 1/16" ply is laminated on the inside from the firewall to the front door/wing mount spruce.
I then started assembling this as per pics.

m_005.jpg (31.7 KiB) Viewed 15912 times

m_006.jpg (32.23 KiB) Viewed 15912 times

m_008.jpg (26.02 KiB) Viewed 15912 times

m_009.jpg (37.03 KiB) Viewed 15912 times

The door cut outs are marked and scored ready for removing.However the removal of the front door left such a weak area I had to glue it up again and reinforce with some ply to get the strength back.the rear door is not as big as the plan because that left a fairly weak area too,so I shortened it by about an 1".

[Peter Siggins]

Usual typos - won't be the last - first sentence should read the firewall - not the COWL on the plan.

More to follow as I shrink the pics

Pete

[Peter Siggins]

Thye above pics show the sides which are epoxied onto the 3/8" ply undercarriage plate ,which is the start of assembling the fuselage.I made a mistake earlier that the fuse sides 1/4" balsa sheet finshes after the rear door and has 1/4" x 3/8" longerons spliced into the sheet to the tail end.

m_DSCF0704.jpg (19.4 KiB) Viewed 15865 times

This shows the size of the front door which was sealed up again

m_DSCF0742.jpg (17.67 KiB) Viewed 15865 times

This is the rear door which I kept but reduced its size slightly

m_DSCF0743.jpg (26.23 KiB) Viewed 15865 times

The rear door opening with trial seat in place

m_DSCF0744.jpg (29.4 KiB) Viewed 15865 times

the rear door with blocks glued in to screw hinges onto

m_DSCF0745.jpg (20.28 KiB) Viewed 15865 times

The rear door hinged - hinges fro B&Q cut down to size.

m_DSCF0745.jpg (20.28 KiB) Viewed 15865 times

I made an instrument panel from bits i had in draws - not necessarily scale but look reasonable

m_DSCF0741.jpg (22.97 KiB) Viewed 15865 times

The rear seat made from blus foam tried in place
I have lost a number of pics showing the construction of the wing joiners and the method of strengthening the assembly with 1/8 piano wire which is across front and rear wing joiners ab=nd notched into the spruce uprights - the following pic shows after all this assembly has been comleted

m_DSCF0778.jpg (35.22 KiB) Viewed 15865 times

The top is now solid and as can be seen the 3/8" wing attachments fitted
if still OK i'll post more later

[Peter Siggins]

Ther are some problems loading pics as you cannot see what is being posted till it is submitted = hence some duplication - i'll get used to it yet

Pete

[Peter Siggins]

Computers are sometimes so useful - other times ******* not
However i found some pics which explain better the way the wing mounts are secured with piano wire

m_DSCF0717.jpg (26.85 KiB) Viewed 15754 times

m_DSCF0718.jpg (27.04 KiB) Viewed 15754 times

m_DSCF0719.jpg (28.53 KiB) Viewed 15754 times

The ends of the piano wire are tagged into the spruce uprights below window level.A grooved balsa piece of 3/8" sq is then hysoled to secure it to the spruce.Where the 3/8" ply wing mounts are the wire is secured by 1/8" ply top and bottom and capped with a 1/8" ply full width and depth capping.It is suprising how solid this makes the wing mounts back and front.
The next pic shows the nosewheel mounted on 1" x 3/4" beech bearers,this is fitted into notches in the firewall and carries the servo and closed loop steering .

m_DSCF0720.jpg (43.48 KiB) Viewed 15754 times

The elevator servos were mounted internally in the rear of the fuse back to back - so one had to be reversed using a mix on the transmitter ,worked fine

m_DSCF0721.jpg (25.27 KiB) Viewed 15754 times

m_DSCF0723.jpg (29.64 KiB) Viewed 15754 times

This left a short 3mm pushrod to each elevator half
Some more pics of nosewheel attachment with mounting brackets - i bought these from Custom retracts in Australia because he had already made some for another Tripacer being built - great quality - came with the steel mounting brackets shaped to give the correct angle of rake on the nosewheel

m_DSCF0726.jpg (41.43 KiB) Viewed 15754 times

m_DSCF0725.jpg (29.47 KiB) Viewed 15754 times

[Ken Bones]

Keep it coming.
I have played with about 4 of the full size doing interiors.
Ken

[Stuart Solomon]

Oy, Siggy, how dare you mention that other wood ? ;-);-)

[Peter Siggins]

Thanks for the encouragement Ken,I am finding it more difficult posting in retrospect than as you build.
There are some areas very short on pics for detail,so if you can bear with me I'll do what I can

Cheers

Pete

[Peter Siggins]

Sorry Solly I'll put 20p in the swear box.

[Ken Bones]

Perhaps I can make up for Pete's big mistake Stuart

[Stuart Solomon]

Aay Ken, how many sticks ?

[Peter Siggins]

I made the undercarriage from dural strip 1/8" x 3" and used 1/4" piano wire for the axle through the dural - pics may show better

m_m_DSCF0748.jpg (30.34 KiB) Viewed 15438 times

m_m_DSCF0749.jpg (18.33 KiB) Viewed 15438 times

m_m_DSCF0750.jpg (33.21 KiB) Viewed 15438 times

I then made the shape - triangular by epoxying some 1/8" light ply and glassing to the alloy this was reinfoced by a 'step' from aluminium angle bolted through

m_m_DSCF0753.jpg (41.46 KiB) Viewed 15438 times

Time to start the wings

m_DSCF0710.jpg (50.82 KiB) Viewed 15438 times

m_DSCF0708.jpg (34.96 KiB) Viewed 15438 times

The carbon tape in the bottom left is to reinforce the wing tongue box which thread onto the fuselage
The flap hinges were made from 1/8" fibreglass sheet and glued in line using piano wire - tthe flaps are actually bolted with 3mm cap heads and washers with nylocs .

m_DSCF0707.jpg (29.55 KiB) Viewed 15438 times

[Peter Siggins]

The elevator control; horns were made from the same 1/8" fibreglass sheet and doubled up with a 3mm ball driver for security

m_DSCF0728.jpg (38.85 KiB) Viewed 15436 times

m_DSCF0736.jpg (27.37 KiB) Viewed 15436 times

m_DSCF0737.jpg (26.03 KiB) Viewed 15436 times

Ihad finished the instrument panel and fitted it inside - probably not totally accurate but does the job!

m_DSCF0774.jpg (37.92 KiB) Viewed 15436 times

m_DSCF0780.jpg (36.78 KiB) Viewed 15436 times

[stuart knowles 1611]

Very nice building