I was wondering if i would be hurting the performance of my pt40 if i built a straight wing with no dihedral. I built the first one with the high dihedral and now im bored with it.

I wouldn't take it out completely, but you could reduce it to less that the original "Sport" wing IF you are ready for it (You ARE using ailerons aren't you?)

yes i am using ailerons. I started flying last summer and soloed in a month. By the end of the summer is was trying some arobatics but with the high dihedral it made the plane feel sluggish. I can get i to roll and even fly inverted but it's like you have to force everything to happen, it doesn't feel natural. I know it's a trainer but i would like to get as much out this pt40 as possible. Is 1/2" or 3/4" enough dihedral?

I built the PT 40 trainer and both wings, A with high dihedral and the B Sport Wing version with less (About 1 1/2 inches. I found that going to the high rate set-up and a .46 engine gave me about as much performance capability as I would think could be expected from such a large flat bottom wing in the B Sport Wing set up. Built both wings with the ability to be bolted in or rubber banded which gave me the abiltiy to switch swings to match user experience and ability. It's been a very versatile and durable trainer. I agree that eliminating all dihedral is not going to do much. It's a high lift slow flying wing with a long tail moment amigo. Maybe it's time for something like the Rapture. You can build it for not much more than the cost of another wing. Best of Luck! Blue

I would vote for stepping up too. Even after removing the dihedral, you still have a flat bottom wing. Take a look at the Midwest Aerobat. I reviewed one last summer, and it was fantastic.

http://www.rcuniverse.com/magazine/a...article_id=164

Thanks for your advice guys. I was looking at a gp super sportster till i made a newbie building mistake. I was helping my father-in-law build his pt40 and built two left fuse. sides. ooops. So my LHS owner sold me an entire kit at cost. So there went my savings for a better plane. So now i have two pt40' and figured i would make the second one as manuverable as possible. Thanks again.

We have a local club member that took all the dihedral out when he replaced a broken wing. Flies GREAT that way. Its not as good at self-leveling... but it does better aerobatics than the reduced dihedral shown in the plans.

I have seen them with the max dihedral, the lower listed in the plans and this flat one. ALL are good. I recommend just skippng the maximum dihedral version though unless doing 3 channel without ailerons.

Three or four members of our club have built a straight wing for the PT-40 and have turned a good though docile trainer into a pretty nice sport airplane. Nice thing is if you keep the original wing too, you can always revert to a trainer to help a newbie out.

Those who flew the straight wing version said the airplane was much more responsive, faster, more maneuverable but less forgiving. They had fun; made me wish I'd have kept my original PT instead of selling it. Go ahead, make the modification. You'll never regret it.

thanks guys. I think i will build the wing straight seeing i have the trainer wing as backup. I got a 46fx for it so im hoping with the change to the wing and the bigger motor it will be more what im looking for without buying a new plane.

Next time, instead of buying a whole new kit just for a few parts, just buy the balsa and cut them yourself. You have the originals to use as a template.

Just a thought re your plan to build the new wing "straight", I assume meaning no dihedral. Remember that the GP method of building with the wing jigs on each end of the wing, weight on center section etc. also builds in washout. (progressive decrease in wing incidence as you go from fuse to wingtip. It seems to me that you would still want washout in that big old flat bottom wing even if you built the leading egde flat or "straight" as you say. Think about it. You could still build in the washout by jigging up the TE as was done in both versions of the GP design. Better aerobatics is one thing. More tendency to stall is another. Either way, best of luck, Blue

A PT-40 was my first trainer, and like you after a while I kinda got tired of it. It had dihedral and only a Fox 40 for power. I took out all the dihedral and built the wing flat. I also cut out the wing saddle a little so the wing would sit down more on the fuse, kinda like a stick. I also swaped engines and put in a 46FX, and turned up the rates a little. The plane became 100% funnier to fly. It could fly inverted easy, do very good point rolls and snaps. Also it held a beautiful knife edge with some speed without any coupling issues! It became less effected by wind and went were you pointed it. It still landed at the same speed as it did with dihedral. I'd say go for it and have alot more fun, even after flying for over 5 years now I still pull my PT-40 out just to show everyone what it actually can do! Keep us posted on what you do, and how everything turns out! Goodluck!

I built the PT60 as my trainer years ago....obviously the same plane just bigger....I fly it with an OS 65LA. With this combo, I can get it to HOVER for a couple of seconds and could possibly do it a little longer if it had more ELEV and RUDDER. Obviously this is NOT an aerobatic plane, but that doesn't mean that you can't try....I still use this plane to teach with ad when people ask me what it can/can't do, I just show them......One OLD FART got on my case once because I was flying inverted about 1ft of the deck....He walked up to me while I was flying and said..."THAT PLANE AIN'T MEANT TO FLY LIKE THAT".........I didn't say anything, but you can gues what I was thinking.

I would have to agree, buying just the parts though wouldn't have been as nice for the LHS. Of course, with the rates the LHS charges for balsa and lite ply, the kit was probably cheaper. I started with a PT 40 too and loved it. Just remember once you remove the dihedral, the plane will not correct itself if you get banked too steep. Have fun.
Hey Great-North, if you get MAN or FlyRC, check out the new World Models/ Airborne Models Sky Raider Mach II. At $69.00 for an ARF you can't beat it. The only thing I would suggest is replacing the fuel tank hardware, I have always had trouble with it and on here heard that others did too. Here is a link: http://www.airborne-models.com/ or http://www.theworldmodels.com/para/p...?airplaneid=69

Good Luck!

thanks for your reply's. I am almost done building it. Im planning on extending the the rudder and elavator for more control. It will also be a taildragger. I can hardly wait till the snow melts up here so i can try it out.

My first one had the dihedral.Ran into a fence and busted the wing in half.

Took it home layed it on a flat table and put the glue to it.If anything,I like it better.

Not a giant difference,but a little better.

Good luck
Walt