AeroTech Pitts Python 50cc

Having decided that getting the fuselage down stairs and into the drive so i can fit wings and check CG may be more challenging than I thought. However, my better half has graciously allowed me to assemble it in the guest bedroom where there is more space. Then "panic mode" cut in whilst assembling. The interplane struts don't follow the wing contours. Scratching head and thinking I have bought a "Dummy". Looked at the "manual", a picture book in reality. No idea. As I was just about to find a large hammer and axe and end it all, I had one thought. Are the struts different lengths, they don't look it. Pulled out the tank again and removed centre wing section. Now pulled out struts........................... Bloody hell! There is a slight difference. Right then I will swap them round, nothing to lose. Refit centre wing, slide top wings on to tubes and place struts in their supposed positions. They now fit! :woohoo:

So Brian, your not the only one that gets sudden out of the blue issues.:lol: .

Phil
I see the pilot is lying under the wing looking puzzled!

Simon O wrote: Phil
I see the pilot is lying under the wing looking puzzled!

:lol: Yes, that is Mutley. I rescued him from Dastardly Dick as he had not had a medal as promised. Even he was baffled by the strut issue. Heh! Heh! Heh!

All the strut brackets have had flange nuts fitted. As these type of nuts have a wider body it gives more surface area for the epoxy to bond to. Once the epoxy has virtually set I then placed the brackets in an oven at 150 C for 20 mins. This cures and bakes the epoxy rock hard. Whether this idea will stand up to RC flying I don't know but I used to bond industrial diamonds into steel spindles for CNC milling of precision screw threads and they did not come off.

Thanks to Mike's link the fasteners turned up the very next day, Saturday. I ordered some Rivnuts 4mm x 10mm and some Threaded Inserts also at 4mm x 10mm. This gives some options on which is best to use.

The Pitts makers say use a wood screw into the pre-drilled holes to secure the wing tubes in the centre section and wings. :huh: That maybe okay for the Americans with their big SUVs because they don't have to keep unscrewing the damn things. After while the screw holes are going to get loose for those of us who have to dismantle every time. I will modify the attachment of the wings.

Built into the wing centre section are some thick ply blocks pre-drilled for the screws. Also in the wings too. After some thought I decided to go with the Inserts. These require drilling a 6mm hole then using an Allen Key wind them in. My theory is that when the 4mm bolt I am going to use is wound in and engages with a hole in the wing tube it is really only torqueing down on the head of the Insert. If in the future I cross thread the aluminium inserts I only have to wind them out and replace. The centre section is done.

Now I have a bit of quandary that I hope someone can assist with. I could do the same method with the wings but in practice I am thinking that any slight change in dimensions due to temperature or humidity might make engaging the bolt difficult. If I make the wing tube hole slightly larger then the wing may not sit closely up to the centre wing leaving a small gap. My other thought was and if I heard correctly from Pete Chilver and his RockStar Bipe that his Flying wires keep his top wings in place. Therefore I will hang fire on this part of the job for now.

You shouldn't have a problem lining up the bolts Phil. The inserts have a hex"socket" which is slightly larger than the tapped hole,this helps steer the bolt into the thread. I use these inserts too, usually with nylon screws but when using steel screws, I lube the screw with a spot of WD40,