New Airplane Pics

LAST EDITED ON Aug-02-04 AT 09:46 AM (CDT)
 
Here is a picture of my new airplane. Notice the airplane has no tail fin. It has a McCoy 35 lighting blue head converter from RC to CL. The muffler is from a OS Max 25 engine. The prop is 10x6 master air screw plastic. The 1st flight the airplane was nose heavy I figured it would be heavy because CG is about 1/4" off according to the plans. I would rather have the 1st test flight nose heavy than tail heavy. I removed the muffler on the 2nd flight and the airplane flew excellent. I have extra engine mounting holes so I can move the engine back 1/4" to 3/4" if I need to. I have a tiny bit too much wing weight so I need to fix that tomorrow. The fuel tank is metal 1.125" tall x 2" wide x 3.5" long with a clunk and air pressure from the prop. The fuel tanks works excellent the engine never missed a beat the entire flight. The fuel tank is a bit large, I did that on purpose. If I put only 100 cc's of fuel in the tank I get about a 10 minute flight and with a full tank I get about a 15 minute flight. The fuselage has no balsa wood in the sides it is 1/8" plywood from the nose to the tail with 1/8" balsa on top and bottom and a few holes in the plywood to reduce weight. The weight of the fuselage is about 1/2 the weight of a typical profile fuselage and probably several times stronger. There is not engine vibration at all. Lead outs are about 1" behind CG. I was suprised that the line tension is about twice that of any airplane that I have while flying straight and level. I assume line tension has something to do with not having a tail fin. The airplane flies great, it will do inside or outside loops several in a row, figures 8's, inverted, wing over, no problem at all. One thing that is a bit interesting is the line tension is reduced by about half when doing a manover but I still have plenty of line tension and can do any manover I want. It was a little bit windy almost to the point of being too much wind to fly stunt today but the airplane did fine. Wing was steady at about 5 to 7 mph gusting up to 10 and 15 mph. I thought this was a nice looking airplane before I built it but now that it is build I don't like the looks of the engine sticking straight up out of the top of the fuselage. This is a BAD design and dangerious too. If the airplane ever has to be landed inverted it will scrape the head of the engine and brake off the end of the glow plug. I had the glow plug started fall off several times and fall right into the prop that could be dangerious. I burned my arm twice because of the engine head sticking straight up. I will never build another airplane with a vertical mounted engine unless the airplane design covers the head of the engine. I timed the laps at 5.5 seconds that is just about the speed I like to fly. I wonder if having no tail fin is causing the increased line tension. I think sence the nose of the airplane in front of the lead outs is heaver than the tail section centrifical force is making the nose of the airplane try to pull out more than the tail making the airplane try to fly away from me. The tail fin would pull the airplane back straight and reduce line tension. I think I will put a tail fin on the airplane to see if it reduces line tension, the airplane looks stupid with no fin anyway. I wish I had some type of timer or clock mounted to the top end of my control line handle. It would be excellect for timing laps and total flight time.

LAST EDITED ON Aug-01-04 AT 00:04 AM (CDT)
 
Well, Gary, at least it won't break off the tail when landing upside down. Speaking of which your next expierment should be to add a tail, a short plane as yours is needs a rudder for stability and to help control yaw. Believe me you will like it. And another expierment would be to buy a cheap digital watch and mount it on whichever wrist is free of the handle. Most digital watches have the ability to also be a stop watch. I never fly without one. My flying partner wears a stop watch around his neck when practicing. I think most of your tension comes from the fact that your leadouts are one inch behind the CG.

Hi Gary, I have a Tomahawk with a magnum 25 on it. I lost the rudder off of it. I decided to fly anyway, and to my surprize, I could tell little or no difference in the flying. It would still do all manuveres, including tight overheads. The engine does have one washer under the engine front mounts to kick it our a little. I did add another smaller rudder, just for the sake of looking correct.
Lee

The combat airplanes I've seen are pretty short & sans vertical stab. They still seem to fly ok.

All a verticle stab is good for is to screw up an otherwize perfect inverted landing!
Joe

Thats funny. It was just last week I was thinking about putting a landing gear on both sides of the fuselage. I was also thinking about putting a small fin on both sides of the fuselage too and putting a tiny wheel on the tip of each fin. This would allow the airplane to take off or land in either direction. Which way is inverted???

Gary,

I have seen trainer and advanced trainers like the one you just built with a single wheel, top and bottom, on the front and a rear fin top and bottom, made from plywood, with a music wire skid set into the front of the fin. This might make you more comforatble flying with that engine mounted upright. You could also put a small disk on the outboard wing tip to act as tip weight and keep the wing tip from scuffing.

One thing I forgot to mention is the engine is mounted straight. Plans usually show the engine slightly turned to the outside I did not do that. Also the fuselage is mounted in the exact center of the wing not off set 1" like some plans show.

Looking at the airplane wing from the center of the circle while flying the left wing tip looks like its is about 3" ahead of the outside wing. The airplane is trying to turn away from me that is probably why I have so much line tension.

I put a tail fin on the airplane. The fin is mounted exactly straight with the fuselage. Nothing else has changed. Lead outs are still 1" behind CG. Line tension is less than before. I can see that the left wing tip looks like its is now about 1.5" ahead of the outside wing, not 3" like before. The tail fin must be count acting some of the centrifical force that is making the airplane try to turn and fly away from me. I would assume the larger the fin the more it will counter act centrifical force and make the airplane fly straight instead of trying to turn and fly away. I can also see if I were to move the lead outs forward a little it would accomplish the same thing and make the airplane fly straighter and reduce line tension. This tells me the tail fin does not need to be offset at all.