Bell X-1E

There was a thread about X-1 rockets and rocket glider kits or the lack there-of. That got me looking at what I had done in the past, with X-1's.
I've done a simple X-1 with just a side profile and wing, it flew well, but was a bit heavy for the wing and it had a bit of flex. I also did an X-1A with a small nose mounted tractor with an airstartable 24mm motor mount in the tail.

I decided I'd do an X-1E, it has the nicest lines of all of the X-1 variants in my eyes. It also seems to have the stubbiest wings, but with a slightly wider chord.

It had: A re-profiled super-thin wing (⅜ inches at the root), based on the X-3 Stiletto wing profile, enabling the X-1E to reach Mach 2.
A 'knife-edge' windscreen replaced the original greenhouse glazing, an upward-opening canopy replaced the fuselage side hatch and allowed the inclusion of an ejection seat. It reached a maximum speed of mach 2.24 with Joe Walker at the controls. It was rebuilt from the second X-1 original aircraft 46063.

I simply upscaled a nice 3-view I had to 37" long and about 26" wingspan or so. Due to the profile top view the CG for boost has to be about 3/4" back from the leading edge of the wing where it hits the fuse based on a 33% mac point using the top view and wings as a complex wing planform. I did some glide tests at that setting with a 10% nose up attitude and it arced over which normally means it will be stable on boost. I did move it forward about 3/16" just to be safe and this proved to be very good.

I chose to put the ailerons inboard where the real flaps are, and leave the ailerons as just decorative. The tail is fully movable just because that is easy for me to install on a light structure. I set it up using a single 3.7V 450mah lipo and spektrum rx with three hs-55 servos. AUW is just over 12 oz, mostly due to the 4 oz of nose weight to get the CG right. Wing loading is still under 7 oz/sq foot.

2 flight tests this morning in about 10 mph wind gusts proved uneventful. I had chosen a hair too much glide up trim on the first flight, and reduced it for the second. Really nicely behaved, roll and pitch at slow speed were very responsive, but not overly so on boost.

I'll try to get a video tomorrow.

Frank

Very very nice! :grin:

I got some good flights this morning.

I also did an experiment using a standard casing with the E-6 reload. I measured the internal length of the standard casing/forward closure and it is slightly longer and will not provide sufficient tension to compress the o-ring. In addition, the forward closure has a little flange on it that the liner tube would slide over when closing the closure and reduce o-ring tension even more. The nozzle pushes on the liner tube when closing to provide the tension. On the endburners there is no forward flame so no o-rings required there. I needed something to butt against that flange and be the full internal diameter.

Aerotech sells .865 by .032 fiber washers that they use in the F-12/E11 reloads that would work, however I went to Ace hardware and found a stainless steel fender washer that measured .038 thick and .872 diameter(close to 3/4"). I spent a minute with a file reducing the diameter to .865 and inserted it. It gave the proper depth and o-ring compression was correct. I did put a very small plug of jb in the ejection hole just to keep any soot from going forward when the motor burns out. This will not work with the non endburning motors, but with the endburners there is no forward flame. Interestingly the standard casing is lighter than the rc casing, and with the washer installed is only 3 grams heavier than the loaded rc casing. I flew it in my X-15, even with it sticking out the back a bit further, I did not need to adjust my glide trim or my CG, worked perfect. This is not an NAR approved loading so you can't fly it at launches like that, but if you are on your own, it might provide a cheaper alternative to the rc casing. I got the forward closure and casing for $30 and the washer was 25 cents, and used the rear closure from my rc casing.

Frank

Here are some flights, the last one is actually the first flight where I figured out I needed a bit of aileron trim just in glide, I've programmed that on my flap/glide trim switch and that is what I used for the first flight in the video.

[video=youtube;RlZvsxGcEbg]https://www.youtube.com/watch?v=RlZvsxGcEbg&feature=youtu.be[/video]