Proposed Pulsejet U/C Flight Test Platform

[larry cottrill]

Sometimes our homebuilt engines get pretty ugly, but that's no reason they can't be flight tested on something good-looking! This proposed design is half good-looking, the other half being a flat surface on which to mount your small pulsejet and ancillary junk [such as the fuel tank]. The outside [away from the flyer] is a fully formed half-fuselage, so it will at least look decent roaring past the admiring crowd.

At this scale, it will only fit Dynajet / FWE size engines very well - for a standard size Chinese, it would need to be scaled up some. This is just a semi-scale model, of course. Some of the NON-scale features:
- Wing lowered and horizontal empennage raised for more spacing from hot engine
- Lots of thin sheet aluminum heat shield to protect the airframe
- Larger than scale wheels, so I can fly it off a grass field
- Extended landing gear for better ground clearance
- No wing dihedral and flat-bottom airfoil, for ease of construction
- Cockpit canopy is carved and painted, not clear
- Engine, fuel and control systems are fully exposed for ease of maintenance, mods and starting

All of that nothwithstanding, it should still be a pretty fine looking model of a full-size craft that is a crowd-pleasing classic. Many colorful scale paint schemes could be used, so I didn't show any of that, except for a couple of scale insignia locations. Though designed as an F-80, it can just as easily be built as a T-33 with the few modifications shown.

The model has a wingspan of just inder 1 metre, so is reasonably compact for a jet model. With careful construction, I believe I could build this craft to a weight of under 2 pounds [1 kg], not counting engine, fuel and nose ballast !!! A model this size should be very fast with a Dynajet engine, probably better than 100 MPH easily.

L Cottrill

[Anthony]

Nice work Larry!

I've got a take on R/C pulsejet testbeds but I have a hard time drawing planes on a computer...

[larry cottrill]

Interesting design, Larry. It's amazing how asymmetric control line craft can get and still work.

What are the chances of you flying your V-1-like plane again? It would be great to get some photos of it in flight. You could do an issue of Jetzilla on using PJs on control line craft.

Ben, as I've stated before, flying the old buzz bomb trainer is more work than fun - it weighs six pounds, has a line pull of about 25 lb using 80 ft control lines, and takes half the circle just to lift off the ground. Of course, it badly needs a new paint job and the de-rusting of all the music wire parts and re-testing the pull strength of the control line leadouts. I DID put new baffling in the fuel tank a few years back, and bought new olive drab dope to paint it with. I'd also need to buy new control lines for it, since my old 80ft lines are long gone.

Keep nagging ... you might convince me some day. Remember, the last time I flew it, there was no such thing as a camcorder. In fact, Super 8mm film was still a few years in the future!

I suppose sometime I could at least get it fixed up and painted and get a few photos of it with the Dynajet happily strapped onto the top of it.

L Cottrill