problem with take off

[eseeweb]

Hi
We are using e-flite apprentice 15e. We used to fly on parking lot and have no problem taking off from concrete. After switching to grass field (joined a local club which fly off from grass field), we experience problem with taking off. First the foam wheel seems to not liking to move on grass. After switching to rubber wheel, it is better. But half of the time, it still try to tip forward and it nose run into grass when trying to take off. The problem is worst when it is windy.

Any suggestion, i afraid if i keep doing this, my motor and nose is going to need to be gone...

thanks, Ted.

[gramps2161]

I have the same problem at my club the grass grabs the wheels wants to tip onto the nose. I have learned to give it full up when I am taking off and I don't take off scale it is full throttle and then I back off on the up as the plane starts to lift off. I also switched over to bigger thin tires they go through the grass better and less grab. Even the big gassers sometimes nose over on our run way. We tried to get the pres. to cut it shorter, but he won't as it will die and then the poor gas guys will have to contend with sucking up dust into the carbs.

[pd1]

Here's a picture of a plane I fly off of dense grass. I had to get wheels so large that they look like clown wheels.
That's a problem with a small plane and tall grass.

[eseeweb]

Thank you for the quick reply. What wheel size generally use on grass. May be I should look for bigger wheel.
Thx.

[josephcharles]

When I taxi out I give the plane up elevator to keep the plane from nosing down until I get up air speed. keep in mind that you don't want to give it to much up, just enough to keep the tail down a slight bit and as you gain speed and lift slowly give it more up elevator. Remember that you want the plane to get up on its wing before you take off. This is not an e-z task and should be practised with small increments of up elevator. Between larger wheels or balloon wheels and a tiny bit of up elevator you should be able to get the tail feathers to stay slightly down until you can get up airspeed and gain lift. Scale planes need to get up a good amount of airspeed. I would also ask the President of your club if you can spray a natural substance to stump the grass growth and find yourself an area that you can take off that has short grass and goes straight into the wind. Another thing to take into consideration is C_G! I know that most people set their C_G a slight bit on the nose heavy side but try to lean to a more even C_G. I'm not saying that its not good to have a tad bit more weight forward of the C_G but try to have a slight bit of nose weight. A nose heavy plane flys but a tail heavy plane dont fly at all unless its a 3D bird. One last thing I've done is to shim the landing gear so that its pitched forward by putting washers or a spacer behind the bolts or screws that are on the trailing edge of the wing side of the landing gear mount. You can also bend your gear rod forward a tad bit, this only works if you have a gear that is made out of round stock. shimming don't work well on retracts without a ton of reconfiguring. If your not an experienced pilot your best bet would be to shim or bend the gear forward, Do not bend the gear while its on the plane because you may crack the mount and end up with two uneven gears. Do this in small increments so that their is no unneeded stress on the gear mounts and or wing. Happy landing's

[CrimzonRider]

Originally Posted by eseeweb

Hi
We are using e-flite apprentice 15e. We used to fly on parking lot and have no problem taking off from concrete. After switching to grass field (joined a local club which fly off from grass field), we experience problem with taking off. First the foam wheel seems to not liking to move on grass. After switching to rubber wheel, it is better. But half of the time, it still try to tip forward and it nose run into grass when trying to take off. The problem is worst when it is windy.

Any suggestion, i afraid if i keep doing this, my motor and nose is going to need to be gone...

thanks, Ted.

I put these on my app15e, kinda funny looking but I can take off from anywhere! I live on a ranch, with lots of rough dirt grass, gravel. No probs tipping over at all.

http://shop.dubro.com/products/produ...7.0.0.0?pp=12&

hope this helps
have a good one
cr

[pd1]

Originally Posted by eseeweb

Thank you for the quick reply. What wheel size generally use on grass. May be I should look for bigger wheel.
Thx.

Bigger wheels do help, two and a half inches to three inches will work for most cut grass surfaces.
If the grass is still too dense, you will have to get larger wheels.

Also as was said, keeping the up elevator in until you have flying speed will help a lot too.

Paul

[eseeweb]

The rubber wheel that i brought to replace the foam wheel is around 1 3/4 inches. i will try this:
a) get a bigger and thinner wheel
b) take of with up elevator
c) bent the gear forward a little bit

any more suggestion, please feel free to let us know...
If weather permits, i will be out at the field this week and try out different ways, hope I will bring back good news...

thx, Ted.

[wolfewinde]

Bigger wheels will make a world of difference - that is probably all you need. The ones you are using are definitely too small for grass.

Wolfe

[eseeweb]

Quick update for my quest to take off properly
I just came back from one of my friend's house. We have switch all 3 wheels to 3 inches size. Also, lowered the back wheels (15e is a tricycle plane), so the nose point upward a little more.
When i measure the old wheels, here is the sizing...
15e original - 1.25 inches
2nd set (i changed earlier) - 2 inches

both are not working with grass. We hope the 3 inches one will give us better/smoother take off. Will update once i try it tomorrow.

Thx for all the suggestion...

[C140]

I know an Apprentice is not a Cherokee 180, but there's some good stuff in here for the technique side of things.

Soft Field - Take-offs and Landings

[eseeweb]

thanks all for your suggestions... with a 3 inches wheel, today i have no problem taking off.

[CrimzonRider]

Originally Posted by eseeweb

thanks all for your suggestions... with a 3 inches wheel, today i have no problem taking off.

Congrats......Kinda like Four wheel Drive for you plane...isnt it!!

have a good one
cr

[FlyWheel]

A long strip of short pile carpet?

Posted via Mobile Device

[pd1]

Welcome to the clown wheel club.

[gramps2161]

Does add character to the plane those over sized wheels, but it is a good trade off though to be able to take off and land with out the final flip.

[eseeweb]

yes, oversized wheel look funny in a way but it works. thx to all. On a second thought it look cool too... at lease these wheels are taller then grass and i can see them.
I guess i am stuck with oversized wheel from now on...
again, happy father day...

[JackM]

I wonder how much this has to do with the position of the axle in relation to the CG and thrust line.

My first plane taxied and landed fine. I bought a mini-telemaster (tail dragger) at a swap meet that had numerous problems including nose over in takoff and landings. I changed the wheels to larger ones with out success.

My next step is to check the axle position in relationship to the thrust line and CG. I am thinking of bending the landing gear to move the axles further forward of the CG.

I just looked at Andy Lennon's R/C Model Aircraft Design book and am going to compare the mini-telemaster with his basic proportions drawing. I am guessing that the landing gear on this plane is going to get bent a little to position the wheels forward a bit.

Jack

[pd1]

Originally Posted by JackM

I wonder how much this has to do with the position of the axle in relation to the CG and thrust line.

My first plane taxied and landed fine. I bought a mini-telemaster (tail dragger) at a swap meet that had numerous problems including nose over in takoff and landings. I changed the wheels to larger ones with out success.

My next step is to check the axle position in relationship to the thrust line and CG. I am thinking of bending the landing gear to move the axles further forward of the CG.

I just looked at Andy Lennon's R/C Model Aircraft Design book and am going to compare the mini-telemaster with his basic proportions drawing. I am guessing that the landing gear on this plane is going to get bent a little to position the wheels forward a bit.

Jack

Bending the landing gear forward will help some if the plane is nosing over on a smooth surface.
If the cause of the nose overs is the rolling resistance the grass causes, then it might not help.

Bending the gear too far forward can present a whole new list of problems.

[dkrhardy]

Bending forward does well on grass. The only real issue you may have is if you go too far forward it may change the CG. Having said that, I have bent gear forward and had no ill effects, not a one. My bending was MAYBE a half an inch. 0.5" The gear is usually very close to CG anyway and a small movement may not cause you any problem. If you bend 'em, just recheck CG.

[JackM]

pd1

I bent the gear so that the wheels are just forward of the LE of the wing. I bent the gear about 15deg bend. The wheels were actually under the wing when I got the model. I plan on testing at lunch time.

What possible/probable problems present themselves when the wheels are too far forward? What would happen if I had the wheels up near the prop?

The gear is pretty easy to adjust (bend) so I may play with it a bit just to see what happens. This plane is a learning experience so I plan on playing with various aspects once I have it flying pretty good. Change one thing at a time and observe.

Jack

[JackM]

Originally Posted by dkrhardy

Bending forward does well on grass. The only real issue you may have is if you go too far forward it may change the CG. Having said that, I have bent gear forward and had no ill effects, not a one. My bending was MAYBE a half an inch. 0.5" The gear is usually very close to CG anyway and a small movement may not cause you any problem. If you bend 'em, just recheck CG.

That is reassuring!

Jack

[JackM]

Just got done testing the telemaster. Major improvement with only minor change in CG (actually better) . Once I have a chance to flay a bit I may put the wheels even further forward to see what happens. I tested the new wheel position in the back yard which is pretty lumpy/bumpy and larger wheels would help. Can't wait to try a ROG instead of just pitching the plane.

Jack

[pd1]

If you look at the picture I posted The wheels are positioned ahead of the leading edge of the wing. I like them there and they work well there.

If I fly off a smooth surface, the tail raises by itself while the plane is on its take off roll. It is easily controllable and the plane flies off when flying speed is attained.

If the wheels are too far forward, the tail won't raise by itself.

If you are overpowered it won't matter much but if you are not the plane will be forced to take off nose high. Stalls are common when taking off with the wing already at a high angle of attack and not enough excess power is available.

Landings will also present a few different problems, the plane will have to be landed so it hits all three wheels at the same time or it will bounce.

So moving the wheels forward usually has benefits, as long as you don't go overboard.

[JackM]

pd1

Your axles appear to be directly beneath the LE but it is tough top tell from the picture.

Both of our clubs flying fields have grass runways. I assume that our grass absorbs some of the energy in landing but also creates drag on the wheels. I am hoping the wind dies down by this evening to try a ROG!

When I got this telemaster it was way tail heavy and wouldn't have flown much less taxi on the runway. After doing a bit of renovation, adding two chunks of brass, bending landing gear I hope it will fly well.

Jack