Project TCOEB (This can only end badly)

[TehMaxwell]

Hey all,

Recently I decided to invest in getting the electronics to build a flitetest power pod, as it seems like a great idea for me, especially since I like to build my own things and explore all parts of the Hobby (I've only been flying for a few years, if that!)

So, I am particularly intrigued by gliding and sport planes, the sort of thing that has an ok glide slope but can also take the speed if you feel like it. So I have built a prototype version, so I can see what works and what needs to be changed.







I have done a few glide tests and it looks promising, if a little chunky, at the moment I am just using batteries to move the CG around as I don't have the electronics.

Things I have noticed are that:

-The tail booms need to be much thinner, they are just to big and chunky, masking the plane look awkward and adding extra weight. But probably not that much extra strength.
-The rudders need to be bigger.

What isn't clear from the pictures is that, I plan to slot a powerpod into the back of the central fuselage, so hopefully this will be eventually accessible for all those that use the swappables series!

I hope you join me for the journey in this design, and, any thoughts?

 

[Ron B]

make your boom triangular instead of square and you will have strength with 1/2 the weight.
just guessing but you may need a longer nose on the fuselage to get more forward weight to help offset the booms and pusher motor.
I have a pusher and have my batteries up against the nose as far as it will go and still had to add weights to it.

 

[engineer]

You've got the right ideas going there, Max. I definitely think the rudders need to be taller, maybe by another 50%.

I also agree with everything Ron's got there. For Triangle booms, I'd try to make sure the bottom edge is a fold, so the paper helps with rigidity. I might suggest the triangle booms be 80% tall as current square tubes and 60% wide.

Looks like a good start, keep us updated!

 

[TehMaxwell]

Hey guys,

Thanks for the quick replies, some awesome idea's which I shall put into practice, I didn't think of triangles although it makes a lot of sense. In terms of folding the booms, I did the same technique of the small front section, it is extremely more rigid. But as I knew I was going to destroy this plane in the end, I did't go to too much effort in terms of structural stability, I just wanted to see if the idea could prove itself.

A larger update will be coming soon, but I have just made a few modifications which I shall be testing tomorrow. The plane has been converted into a more conventional single boom tail design. I want to see if this makes a lot of difference, it definitely reduces weight and makes the plane much more strong. Looks awesome too!

I shall be back with an update soon!

 

[rcspaceflight]

This is how I made the tail booms for my Skymaster. They felt solid, not as solid as square tubes but definitely solid enough. They're thin, just like what you're after.

 

[TehMaxwell]

So, updates on the project. I have done a few glide tests in the single boom airframe and it looks more promising than a twin boom. I think I will stick to conventional glider shapes for now, as this is basically the first time I have scratch built my own design.

It feels considerably lighter and glides much better than the twin boom design. It's also much more robust. Some pictures:





Obviously the same changes mentioned earlier still need to occur, but I think I will keep this as the basic shape for my design, although the tail needs drastic changes. Most importantly though the wing has proved itself, so I can move on to other parts if the airframe. Bare in mind now that this plane will be a tractor design, not a pusher. I will see if I can use the spare folding prop I have laying around!

Any thoughts on this one?

 

[highflying]

It looks good, what foamboard are you using?

 

[TehMaxwell]

It looks good, what foamboard are you using?

Ahhh yes the eternal conundrum of getting foamboard in the UK, without breaking your bank. I wasted a lot of time finding a source but I think I finally cracked it with these guys:

http://www.foam-board.co.uk/5mm-white-foamboard/

Hope this helps!

 

[Zap brannigan]

Ahhh yes the eternal conundrum of getting foamboard in the UK, without breaking your bank. I wasted a lot of time finding a source but I think I finally cracked it with these guys:

http://www.foam-board.co.uk/5mm-white-foamboard/

Hope this helps!

man they charge a lot for foamboard,now I know why Adams isn't available there in the UK ,with the import duty,it would be triple!!

 

[TehMaxwell]

man they charge a lot for foamboard,now I know why Adams isn't available there in the UK ,with the import duty,it would be triple!!

Yep they charge a hell of a lot for foam board in the UK, the supplier I linked previously is pretty good as you get about 25 sheets for that price. But I used to pay around £30 for 2 sheets!

So the next big update on the project, I have designed and built the new tail section, the aim with this was to get much closer to the final design. So it is much higher quality. I have to say I feel I have surpassed myself on this one!







The construction of the central tail fairly simple, using the scoring and bending technique used commonly in FliteTest builds. There is a tapered central spar that runs down the length of the tail, then there is a piece of foam that has been scored and wrapped around it to give the correct shape. As suggested I have increased the size of the surfaces dramatically, so it should be very stable when in the air.

I plan to get the fuselage completed today in spare time. This will use some tabs that will slide into the tale section, so that they can join together at the correct angle. It should also give more strength. I plan to make the nose shorter, taking inspiration from the KA8 glider, so we shall see how that goes. However providing this tail section and fuselage give good performance, I am not inclined to change them, as I think they look great!

At the end of this if you guys want dimensions and some build instructions I can put those together, providing this thing flies well!

 

[HillBilly30]

Hey TehMaxwell,

I have been wanting to build a pusher and your first prototype was the inspiration for my latest plane. Just wanted to say thanks for the inspiration and good work on the development of your plane. Can't wait to see yours flying. Don't want to Hijack your thread.
So, here is the link to mine.

[url]http://forum.flitetest.com/showthread.php?10127-TMQ-1-HUAV-Backwoods-Prowler-Twin-Boom-Pusher