wazzbat

I am going to be building an LT-40 soon and was wondering about the wing dihedral. It will be my first build and my first plane. I am yet to grab a hold of the controls. However - I have been playing about on the Real Flight sim for about a week now and when flying with the PT-40 I am finding it quite hard to stop the damn thing from climbing all the time. Even when I back the throttle off to about 60%, it still climbs. Anyway, what I was wondering is the PT-40 similar to the LT-40 and is it worth adjusting the dihedral when I build it to stop the plane from climbing so dramatically? Or is the sim not as realistic as it's talked up to be? Or is it pretty normal for a trainer to have those characteristics and I should be learning to control the plane accordingly?

I can take off and land pretty good now and can fly about without crashing. So the other thing Iwas wondering is, how accurate are the sims compared to the real thing? Obviously there is no substitute for the real deal but would Ihave a pretty good chance of replicating what I can do on the sim in real life? In other words - Get a plane off the ground, fly in a basic pattern and then land her?

By the way, I don't plan on doing it on my own. I will be getting down to a club to get some training before Iattempt to fly but I was just curious. I was also wondering how beneficial a park flyer would be for practicing? I live over the road from some school grounds so there is plenty of room???

Cheers

Top_Gunn

My Feedback: (6)

The dihedral on the LT-40 is fine, and in any event, changing it wouldn't affect a tendency to climb. The LT-40 does normally need the elevator trimmed so it's down a fair amount. To change this, you'd need to fiddle with the wing or stabilizer incidence: not advisable for a beginner, and not necessary anyway.

If you have a tendency to climb in straight ahead hands-off flight, you can trim it out. If it's just climbing when you come out of a turn, that means you're holding up-elevator too long.

Simulators are pretty good for practicing the left-right thing. Not a lot else, at least for me; especially not takeoffs and landings.

noveldoc

My Feedback: (2)

The LT 40 kit should have some downthrust built in to help with climbing. I know all the Kadets do.

Tom

rlmcnii

My Feedback: (3)

wazzbat,
My re-entry to R/C a few years ago was as yours is now. Simulator followed by an LT-40. A few observations:
1. Spend a lot of time with the simulator (PT-40 is fine) so that you can take off, fly the pattern while maintaining a constant altitude, and land ON THE RUNWAY each time. By doing this I was able to fly my LT-40 on day one. I did have my son-in-law backing me up on a buddy box.
2. The LT-40 is lightly loaded and will climb readily at fairly low power. Mine had a Saito .50 in it and full-power was needed only for take-off and later for mild aerobatics. The plane was normally trimmed for level flight at half throttle. More power requires more down trim and will result in faster flight. Less power=less down trim and slower flight. When trimmed for a given airspeed the plane will climb with additional power and descend with a power reduction. Dihedral functions to return the plane to level flight when its roll attitude is altered from level wings level. You will need to learn to control the airplane. I think many beginners are adverse to moving the sticks, or else they stir them all over the place. In either case, the airplane is controlling the pilot. Not a good situation.
3. Spend a little time to trim the airplane so it will fly straight and level, at your selected throttle setting, hands off. Otherwise, you will be fighting it all of the time. That will slow your learning and , in any event, is most unpleasant.
4. In my experience, the simulator was very accurate and very helpful.
5. The LT-40 is a very nice kit. Build is straight and true and don't over power it and you will be fine.
6. The first time you fly your LT-40 you will probably get a case of adrenalin-induced nerves that you do not get with the simulator. I think that happens to most people, and probably with most people on the first flight of any airplane, regardless of experience. Have fun and good luck.

Rodney

I think the original author is confusing dihedral with incidence. Dihedral has nothing to do with whether or not a plane will climb, it effects the lateral stability only.

wazzbat

Rodney - Yes I was.  And I only just realised it when I read your post - Cheers. 

Rlmcnii - Thanks for your input.  I think you have summed it up pretty well for me.  I shall keep practicing on the sim.  I might try and work out how to trim the PT-40 a little and see if that helps to reduce the climb?  Or better still , try and work out how to download an LT-40 for the sim.  I will probably be putting an OS 46AX on my LT-40 by the way so it should be about right I hope.  Or I might end up splashing out a bit more and getting a Saito?   I like the sound of the four strokes.

Lnewqban

It is about decalage (or longitudinal dihedral):

http://www.rcuniverse.com/forum/m_75...tm.htm#7544125