Built to crash

RknRusty wrote:Doh!
Sorry Mark. Lets give credit where credit is due. Anyway, still a good idea.
Rusty

No biggie Rusty. So long as the tip helps someone, I'm happy to share. I don't need the credit. Just remember to send me my royalties and I'm fine.

The Selfless Mark

Lol the check is in the mail.
I always look at those pliers in the HS, but haven't sprung for them yet.
Rusty

Hey Mark, PM me your address. I don't have many of them, but I can spare 2 or 3. It's a good idea to put washers between the collar and the wheel. Use washers that have a 1/16" (.062) inside diameter. See my recent thread on "making thin washers".. They only need to be made from plastic to work.

https://www.coxengineforum.com/t6468-making-thin-washers

Those Z-bend pliers are cool! I've never seen them before. I use a "Harry Higley" Z-Bender for mine.

RknRusty wrote:Lol the check is in the mail.
I always look at those pliers in the HS, but haven't sprung for them yet.
Rusty

I don't often tell someone, "You need to go out and buy XXX, and do it now!". But I would recommend everyone who is a long term builder and plans to build many models in the future to have a pair of these Z bend pliers. I think they cost me about 11 bucks. A bargain for the consistency, ease of use, and time saved. I just put the end of a piece of wire in the jaws and squeeze. A perfect bend in two seconds. For R/C, I make a Z bend at the control horn, and use an E_Z connector at the servo. For C/L I make a Z bend at both ends, as seen above. I honestly feel these things are right up there with Clecos, the auto-center punch, and a unibit as the greatest tools ever.

The Gushing Mark

roddie wrote:Hey Mark, PM me your address. I don't have many of them, but I can spare 2 or 3. It's a good idea to put washers between the collar and the wheel. Use washers that have a 1/16" (.062) inside diameter. See my recent thread on "making thin washers".. They only need to be made from plastic to work.

https://www.coxengineforum.com/t6468-making-thin-washers

Those Z-bend pliers are cool! I've never seen them before. I use a "Harry Higley" Z-Bender for mine.

Roddie! Thanks for the offer. This place has the coolest people on it.

The Aspiring to be Cool Mark

I got a no-name z-bender pliers and can't figure out how I lived without!

Phil

Well, ready for paint.  I tried to keep it simple, but still ended up putting more time into this than I had wanted.  I should have less time in the BTC-2 I'll start next.




The Simple Mark

Z bend pliers. When I have seen the models on this site - I assumed everyone was using them. Would not have thought of recommending them.



While bending wire with pliers is easy - getting it right isn't. A perfect Z bend in seconds in the correct orientation is a breeze with these.

batjac wrote:Well, ready for paint.  I tried to keep it simple, but still ended up putting more time into this than I had wanted.  I should have less time in the BTC-2 I'll start next.

The Simple Mark

Hi Mark, I think it looks like a successful model, I hope you don't mind if I make some suggestions.

It looks to be in similar style to a Stuntman 23. From the pictures I can't tell exactly how the front end is constructed. But I've learned from lots of full power burials that radial mounts are far more durable. When you make BTC V 2.0, you might want to consider one of the screw-in backplates or other type of radial adapter for the Medallion, which, bye the way is probably the best engine you could have chosen for a trainer.

The long tail and substantial stab will probably make it capable of at least basic loops, though it may need a wider wing chord to get enough lift for that sort of flying. A bit of trailing edge extension could be added later if you get that far along with it.

The long tail is the place where it's most likely to break, so you might want to consider a doubler behind the wing, or shortening the tail on the next version.

I think it'll do the job you need it to, and I think I'll do something like it. I need a couple of trainers I can take over to the church yard and let people fly and not sacrifice my nice ones. My 1/2A fleet is looking pretty sad and neglected right now. I have a tracing of a whole Stuntman and Little Devil on some old sheet rock squares that were my building board some time ago.

Rusty

Hey Mark, Once you get yourself a supply of balsa and plywood, you'll be good to go for the BTC II. Rusty made some good "dimensional" points there... and I've taken note for my next self-designed model... to follow them closely.

We realize that you were limited by the stock you had on-hand with this first design. Like Rusty said; lengthening the chord on the one you just built... at the wing's trailing edge will help when it comes to stunting.

btw... the 2nd model of the same or similar design, always builds quicker!!

Thanks for the input, Guys.  I'm just looking for a plane that'll do the basics.  Wing-overs, loops, basic inverted, extremely lazy-8s's.  I'm going to start with 42' lines, so hopefully the Medallion will keep her tight on the lines for decent sized maneuvers.  I have the throws set to minimal right now.  About 25 degrees max.  I'll increase the throws later and see what I get.  If I need more wing area I'll add later as Y'all said.   Or, maybe just cut out a 1" or 1 1/2" section forward of the stab.  I did a funny thing with the crutch bottom and kinda cross-braced it.  We'll see how that goes.  I didn't want the radial mount because, well, I just didn't.  I simply wanted to do something that I haven't done before. As for doublers and such, a good crash will break those anyway, so I opted to save time and weight now, and I'll glue it back later as will inevitably happen anyway.  I made the moments long because I'm looking for smooth maneuvers rather than tight maneuvers.  The BTC-2 will have closer coupled surfaces going forward.  

Oh, and the BTC-2 will look nothing like the BTC-1.  Doing the same thing would be boring.  I gotta be creative.  I gotta be trendy.  I gotta be hip.  I gotta be fresh.  I gotta use the other sizes of wood in the spares pile, and the other unused engines in the drawer.  I was just sitting down with pen and paper drawing out the lines for the next one before I turn in.

The Hip Mark

Hey Mark, As long as you're getting enjoyment out of it.. That's all that really matters! I find the designing/building process the most satisfying.. myself!

Well, the weather was finally good for a couple of days, so I threw a paint job on the BTC-1.  It’s just a basic blue/white paintjob done on the quick.  It could have used one more coat of white on it, but the only white paint can I had ran out, and I didn’t want to buy more.  I tried to get some decent pictures, but the lighting in this room isn’t that great, and taking pictures of a dark blue plane against a black table didn’t work too well.  I held my Ott light in several positions trying to enough light for decent definition, but no good.  Oh, well.  You get the idea.  It was never meant to be a pretty paint job anyway.






The distance between the wing and stab isn’t really as long as the crappy camera makes it out to be, and the stab isn't crooked like it looks in the pic.  The camera is great for vacation photos of things/people 15 feet to infinity away, but it sucks for close-up pictures. The lens makes the angles close up look off.

Now for a day that: 1) isn’t too windy, b) isn’t raining, and 5) there’s someone to pit for me.

The None Too Pretty Mark

I like it. It looks like just what you need for it to be. I hope you can get out there and tune your reflexes with it soon. How much did it end up weighing?
Rusty

getback wrote: looks good Mark, Did you just prime and sand the natural looking wing? ,clean and simple hope it flys well for you ! videos if you can Eric 

Thanks, Eric. I didn't bother priming, and almost no sanding. I didn't want to spend any more time on the finish than necessary. I'll try to get my son to do some video.

The Unfinished Mark

RknRusty wrote: How much did it end up weighing?
Rusty

Rusty, I pulled out my scale to measure some things for another project, so I figured I’d weigh the BTC-1 at the same time.  It came out heavier than I’d hoped, but at 7.95 ounces ready to fly, it should do okay with the Medallion .049 on it.


The Heavy Mark

Well, I put four flights on this thing. I was right when I said I built it too heavy. The Medallion doesn't have the oomph to pull it through more than a loop. It does fly pretty smooth, though. And I got the balance just right. When the engine dies, it doesn't want to nose down or up, it just floats down in a nice flat glide. I'll try one more time to get the Medallion tweaked for more power, but I don't think I can get much more out of it. I think I'm going to put a Norvel I have on the shelf on it instead.

The Tweaked Mark

Mark,

Just something to chew over. Here is my modified Baby Clown. It's a marriage between an original PDQ kit and a Brodak kit. All said and done it came in at 8.65oz.



It is now powered by a TD, but in it's former life it was powered by a bog standard Medallion. All that is different from then to now is a different shaped fuse, flaps and added linkage.

Halfway between all that I did put a #4 on that Medallion, but it really didn't need it.

Anyway, That Medallion of yours may just need a bit of freshening up to allow it to perform the way you wish it to. The TD cylinder couldn't hurt either   

I should also mention that the Baby Clown could give Rusty's Flite Streak a run for it's money!     
Ron

Cribbs74 wrote:

Anyway, That Medallion of yours may just need a bit of freshening up to allow it to perform the way you wish it to. The TD cylinder couldn't hurt either   
Ron

I'll try it with the TD cylinder to see what happens. I'll also try another prop to see if it gets more bite. If nothing else, I'll put a TD on it to verify performance, then set this plane aside for the Traveling Engine. At least I know the plane's stable and well mannered enough that I wont prang the Travelling Engine when I get it.

The Stable Mark

Well, the BTC-1 was a stable enough plane, but the idea was for a plane I could start expanding my horizons on without crying when it went in.  So, I pulled it out to do some tweaking for better performance, making the BTC-1.1

I cut the canopy and turtledeck off, and cut the tail length down by 1¾”.  It’s more streamlined now.  I also took off the landing gear.  I increased the elevator throw by 1 hole in the bellcrank.  Didn't measure before and after to see how many more degrees of travel that is.   Then I set the c.g. at 25% for now.   It should be a little more peppy.  After tuning, it'll get a clear plastic canopy of some sort.




Unfortunately, when I pulled out my precision scale to measure the weight difference, the scale was dead.  So, I used the digital luggage scale I bought a couple of months ago after seeing Roddie use them on his floating thrust scale.  I’m not sure how accurate it is, but it’s not quite as accurate as the digital scale I’ve been using.  The luggage scale says the new weight is 7.5 ounces.  It feels more than .45 ounces lighter, though.  When I get a new digital scale, I’ll measure it again.

If, after flying it a few more times, it’s still not where I want it, it’ll get a Medallion .09 and more elevator on it.

The Streamlined Mark