OK guys, this time I kept quiet about what I was up to until it was successful. I had and old Nitro Planes BobCat that had a damaged fuselage. I found that Nitro Planes got replacement fuselage's in stock so I ordered one and converted the plane to pulse jet power. Today was my birthday and I was rewarded with a great pulse jet flight. I don't have the video yet from our club photographer but I will get it in the near future and post video if the flight. I will also post some pictures of the build a bit later and some pictures still pictures now of the plane at our flying field today. I still plan to build the Delta/Vortex/Shockwave but this put me in the air much faster.
A bit of added information on this project is: pulse jet engine by Jet Bill, thanks Bill for a great performing engine, fuel setup by Bruce Tharpe, thanks Bruce for all of your advice and support, plane = Nitro Planes BobCat 52, dry weight ready to fly is 7 pounds and 12 ounces, approx. 24 ounces of fuel gave a 2 minute and 47 second engine run, fuel used is 80% methanol and 20% nitromethane. Retracts are robart spring down, air up. The plane was fast but not too fast - maybe 80 to 100 MPH range.
I started this build with a Nitro Planes BobCat ARF that was damaged in a forced landing. The fiber glass fuselage had been damaged but the rest of the airplane was in good condition. I found that Nitro Planes had a spare fuselage so I ordered it and started this build with that replacement. See the pictures below of the replacement process.
I used a fuel bladder made by Bruce Tharpe inserted into a plastic bag which acts as containment if the bladder ruptures. The end of the bladder and bag assembly was placed between two blocks of wood with a hole cut to the size of the bladder end where the blocks squeezed the bladder end and then the blocks were mounted to the fuselage floor with screws. See pictures below:
I made a little platform to mount the Cline regulator, Perry fuel shutoff valve and servo to operate the valve. The fuel system platform was then mounted to the floor of the fuselage with screws. See pictures below:
OK, here is the link to my maiden Pulse Jet powered BobCat flight. http://www.youtube.com/watch?v=nCPS_-CM ... tube_gdata I am sorry for the quality but the video was taken by our club photographer. The only time I can see the plane is at startup, takeoff and landing. Maybe some of you have better eyes than I do.
We had flight number two today with my pulse jet powered BobCat. She started easily and flew great. John did a few aerobatics this time and everything went very well. We used 32 ounces of 80% methanol, 20% nitromethane fuel for an approximately four minute flight. We had two video camera men again but the quality was not there. I will just have to find someone locally who is a professional or semi-professional photographer so we can get some good video of this plane. The plane is impressive and it gets a lot of attention.
I flew my pulse jet again today. The flight started out quite well but about a minute or so into the flight, the engine changed song and lost power. The difference in power was noticable and about a minute after the change in sound, the engine quit. The sudden lost of the engine was unexpected. My altitude was low and there was a stiff breeze down the runway. I ended up pancaking the plane in trying to make the runway. I made the end of the runway but she landed hard and tore the landing gear out. The damage is not too serious and the plane is repairable and will return to the air when I find the time to make the necessary repairs. We checked the fuel supply when we took the plane back to the pitts and found that about 40% of the fuel load was left. I could be wrong, but I think I just experienced my first reed valve failure. When I get the chance, I will check the reed valve and see if that is what caused the change in tone, loss of power and the engine to quit.
Best wished, and good safe flying - Also Merry Christmas and Happy New Yeay to all.