Espritmodel.com Telemetry Radio
Reply
Thread Tools
Old Nov 21, 2004, 02:23 PM
Registered User
Joined Nov 2004
5 Posts
Question
Freedom Flyer No Fly!

A recently purchased Megatech Freedom Flyer no no longer will take off. I fhave no experience with electrics or gas and this is my first electric plane. The first three take offs were simple, quick and uneventful, although each time after reaching a low altitude and trying to turn right, the plane tipped its right wing and out of control crashed. The problem is since that day the plane simply will not take off regardless of how long it accelerates. I have three batteries and they all work the same. I suspect that the 400 motor no longer turns the 6.75" prop as fast as that first day. What is more likely: 1) the inexpensive motor is worn out or 2) the controller is no longer allowing peak rpm? A friend has a prop tach but how fast is fast enough?

By the way before you ask, the center of gravity is just forward of the center of the main wing. Everthing else on the plane I believe functions properly. The batteries weight about 5.4 oz and the 400 motor weights 2.6 oz. The two wire motor does not have the operating voltage on it but does have a part number of 4540226C4G. The plane, fully loaded, weights about 18.4 oz and the main wing is ~34.5 inches. Other than buying a more expensive artf plane does anyone have a suggestion? If you suggest a motor change what 2 wire motor do you suggest?

Thanks for the help, Slowstick58
slowstick58 is offline Find More Posts by slowstick58
Reply With Quote
Sign up now
to remove ads between posts
Old Nov 21, 2004, 04:16 PM
Oops get the hot glue gun
FoamingInMI's Avatar
Lansing, Michigan, USA
Joined Sep 2004
1,240 Posts
First of all, welcome to the Electrics forum! Sounds like this is your first R/C plane you've had a bad experience right out of the box, so to speak. If your plane took off and then crashed on the first couple of flights there was probably something not quite right with it from the beginning, ruling out pilot error of course. Hopefully nothing was damaged in the 3 crashes that would effect it's being able to fly once you get things sorted out.

If the C/G is really ahead of the leading edge of the wing, it will be hard to get the plane to take off for sure. The C/G should be roughly at 25% of the wing chord. Measure the width of the wing and try to move the battery back if you can so that the plane balances at 25%-30% of the chord measured from the leading edge of the wing. That should get you in the ball park.

I'm not familliar with this plane myself, so I did a search and found that it will fly up to 50MPH. That is pretty fast for a beginner's plane, things may be happening faster than you can react to without some more experience with a slower plane.

After you get the C/G close, I'd take it to a wide open grassy area and hand launch it and about 1/2 throttle, give it a good toss and just let it go a ways with no control input and see how it flys. If it looks OK, add a little power and get some altitude before you try any turns.

That's about all I can suggest having never seen the plane before. Others here will probably be able to help too.

Good luck and post your progress.

Gary D.
FoamingInMI is offline Find More Posts by FoamingInMI
Reply With Quote
Old Nov 21, 2004, 04:59 PM
Eye Drather Beef Lying
ElectRick's Avatar
Jacksonville, FL
Joined Aug 2002
2,696 Posts
Your description of how the plane turns, drops a wing, and goes out of control sounds like a tip stall to me. This could be caused by a warped wing, a too far aft CG, plane too heavy, pilot error, a worn out motor, or any combination.
This plane ought to nearly fly itself, if set up properly. Center of Gravity is fairly critical on these small planes. Being off 1/4th inch on a 5 foot span plane is way different than being 1/4th inch off on a 34 inch span plane. It sounds like yours is too far aft, which is BAD for a beginner.Try shifting the battery to get the CG at least within 1/8th inch of where the instructions show it (usually around 30% of the chord from the leading edge). Make sure the battery can't move around inside once it's positioned. That could be disastrous.

While you're checking stuff, strap the wing on, and set the plane on a table. Sight the plane from the front, level with the propshaft. Look at each wing panel leading edge, and compare how each side looks to the other. What you are looking for is warps in one or the other panel. Also see that the stabilizer is level with the wing.

Also, a 6-3/4" prop is a bit much for a direct drive SP400 motor, IMO. Go get a 6-3 and/or 6-4 plastic prop (Cox plastic props work well) and try that. Also what battery pack are you using? The battery may not be able to provide enough amps to that motor and prop combination to fly the plane well.

Try to find an experienced flyer near you to test fly the plane and get it trimmed to fly right. It will save you a lot of grief and money in the long run.

Good luck.

Rick
ElectRick is offline Find More Posts by ElectRick
Reply With Quote
Old Nov 21, 2004, 06:30 PM
Registered User
Joined Nov 2004
5 Posts
Thanks for the quick replies. The first 3 take offs were I thought rather easy, but turning was where I had trouble. Guess I should have practiced level flight and landing first. Anyway, the problem is as I stated the plane simply won't take off. The CG for the first 3 take offs was near the leading edge of the wing as close as I can estimate. Some of my friends at work fly electrics and they as you suggested my CG was two far forward. So I moved the battery closer to the wing and the CG is now I would say about 30 percent of the distance from the middle of the wing to the leading edge but the result is no different. About the only thing that has been different is the first day was slightly breezy and I was taking off into the wind.

While something less obvious may be wrong or damaged, how do you tell when the plane should have enough power to take off? If a measure the amperage draw will that tell me? If so, what should it be? If RPM is a key what should it be? Hope you have some insight into this because I am at a loss. A friend who has experience with electrics has volunteered to help but in advance of trying to fly again I would like to know the plane is capable simply from an engine/battery performance perspective if possible.
Thanks again, slowstick58
slowstick58 is offline Find More Posts by slowstick58
Reply With Quote
Old Nov 21, 2004, 09:27 PM
Registered User
Joined Nov 2004
5 Posts
More info

Some more info: The battery pack is a 7 cell NiMH. I have three and i have tried all three with the same result. The prop is again about 6.75 inches tip to tip and probably 3 pitch (My guess). The motor is supposed to be a 400. If it is what voltage rating should it be? If I were to replace it what voltage rating should I use with an 8.4 volt battery pack?
Thanks again, slowstick58
slowstick58 is offline Find More Posts by slowstick58
Reply With Quote
Old Nov 22, 2004, 08:35 PM
Registered User
Joined Nov 2004
5 Posts
Maybe the last word

At the suggestion of friend I tried the other prop that came with the airplane and it made a significant difference in current draw. The used prop was drawing about 6.3 amps and the new prop about 8.8 amps and sounds stronger. So I guess that was it but won,t know until I fly again this weekend. Borrowed a friends tach but tach only works in sunlight apparently. The old prop turned about 9,000 rpm. It will be interesting to see tomorrow what the new prop turns - faster or slower - what would you guess?
Thanks once more, slowstick58
slowstick58 is offline Find More Posts by slowstick58
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Megatech Freedom Flyer really does fly very good! Michael Heer Parkflyers 46 Apr 02, 2006 06:00 PM
1st West Coast Park Flyer - Fun Fly SchiessCo Electric Flight Events 3 Oct 17, 2002 09:34 PM
slow flyer, ready to fly *look* undecided Aircraft - Electric - Airplanes (FS/W) 2 Jun 30, 2002 03:22 PM
House Fly no Fly KillerWatt Electric Heli Talk 2 Mar 29, 2002 08:42 PM
Another No Fly Zone E-Challenged Electric Plane Talk 60 Nov 04, 2001 04:59 PM