Taking off on a bumpy grass field
 

I wonder how many people suffer from the same problems as me...

Basically over here in England, I am lucky enough to have access to a large area of farmland, for which in terms of airspace, it is superb for model aviation..

However, taking off from the fields can become a nightmare for me.. the ground can be real bumpy and the latest incident was that one of the wheel grommits was forced off.. which was quite a shock as i check them before each take off.. luckily no damage was done to the aircraft, but if this had happened at max throttle I suspect a lot more damage could have been caused.

Does anyone else have problems taking off from grass and do they have any tips ?

I was even considerning asking the farmer if I could use a patch of land as a designated airstrip and maintain the grass level and possibly find a way of flattening the land to get rid of the bumps...

RE: Taking off on a bumpy grass field
 

I've had the same experience. Where I used to fly a farmer had an area and would let us fly from it. It was rough and one of the guys asked if he could level it. We even offered to plant grass. The farmer said sure so some of the guys volunteered on a Saturday and went to work. When we started flying again, the farmer saw how much fun we were having so he came over and watched. He now flys too! It's a blast and there is no formal club there just a bunch of guys getting together and having fun. We have even bought a windsock, tables, tiedowns etc. and the farmer has no problems with is. As long as we clean up after ourselves and are careful there are no problems. We flew on the dirt (it was compacted) for the longest time but eventually the grass came up and now the farmer mows the grass too. All in all it was a win-win for everyone.

But back to your question, I thing I did was increase the size of my wheels to get more ground clearance so the prop is less likely to strike.

Good luck!

RE: Taking off on a bumpy grass field
 

That is So Cool that the farmer flies with you guys now!!!

We 'rent' space from a farmer, too. Our 'field day' is next Saturday, and we're renting a roller to smooth out the bumps. It takes care of anything that would really hurt the plane, although there will definitely be some rolling hills left in the runway when we're finished.

RE: Taking off on a bumpy grass field
 

I've never been there when he's flown but I hear he is pretty good. He has a couple of warbirds. I met him when he was planting beans (he came over to see what I was flying) and saw him another time when he drove his tractor over to cut the grass. Nice guy.
He also drove his small tractor over once when there was about 7 guys there flying. He stayed and visited for quite a while but didn't have the time to fly.

RE: Taking off on a bumpy grass field
 

Get with the farmer and see if he'll let you put in a strip. If your willing to maintain and mow it the only thing he loses is a small patch of land he likely wasn't growning crops on anyway.

RE: Taking off on a bumpy grass field
 

*hrmm*

Ok, I'll admit...I've NEVER tried this in RC, so this is nothing more than a 'what if?" thing....but...

With a full-scale soft-field takeoff, the technique is, basically, to hold full up elevator from the get go. As soon as the plane breaks ground, relax the elevator pressure to let it float in ground effect until enough airspeed is built up to climb out.

The purpose is the same as being discussed here...to avoid bumps and holes and what not. It would seem, in theory at least, that the technique would work for RC as well. *shrug* That way, if you could just find a few feet of relatively "smooth" grass, you could go ahead and get into the air, and avoid the bumpies.

Granted...it's probably a whole lot easier to just roll and plant. )

RE: Taking off on a bumpy grass field
 

I've flown off a bumpy field once and used the full scale soft field takeoff technique with success. It was second nature to me as I fly full scale. :)

RE: Taking off on a bumpy grass field
 

It does work in RC but you have to be good enough to pull it off. I have seen people that don't relax the elevator and continue trying to climb only to find their airplane catwheeling down the runway.
Our field is new, this will be the 3rd season flying from it. The soil is mostly clay so grass tends to grow in clumps. I went out their last Sunday and tried to fly. The grass clumps sat about 1-1/2" or so above the rest of the ground. I ripped my nose gear apart just trying to taxi out. The field will be rolled out this week and tomorrow is cleanup day. If there is not a vast improvement I will be flying at the other clubs in the area.

RE: Taking off on a bumpy grass field
 

Yep, it works with models, I used to fly from a field under simular conditions.

You can also do a half-way version, where you just get the nose wheel up in the air, and go down the runway doing a "wheelie" while the plane accelerates. It's a bit of a balancing act with the elevator, but it will get you there.

Tail draggers also often do better on bumpy fields and tall grass and don't look as silly with huge wheels.

RE: Taking off on a bumpy grass field
 

Makes sense it would work, i guess...they're still airplanes, and do what airplanes do for the same reasons airplanes do them. *heh*

Gotta admit though...having only recently started practicing them in full-scale, the IDEA was 'second-nature", but I don't think I can quite claim the technique would be *heh*

So, in other words, EXACTLY like full-scale, eh? [X(]

RE: Taking off on a bumpy grass field
 

That is the STOL takeoff on a tricycle gear. Full up elevator till the nose lifts, ease off to maintain that attitude, upon liftoff stay in ground effect until achieving climbout speed and then climb out at maximum rate of climb speed to safe alititude and then ease of to best rate of climb speed. I'd think with a model it could be pretty dicey if you encounter a large ant hill while still in ground effect. :D

Would a hand launch would be possible?

Regards,

Clay

RE: Taking off on a bumpy grass field
 

Since no one mentioned size, 3" wheels are the magic number. Any smaller than that and the wheels are trying to try to push through the grass rather than roll over it. You will notice a big difference even if you are just increasing size from 2 3/4" wheels. :D

RE: Taking off on a bumpy grass field
 

Our field has a nice paved 50x500 runway. Woe to anyone that runs off it though. We are in pasture land and the ground squirels have hundreds of holes all around our runway. They especially like the edge of the runway and man, if you drop a wheel off, chances are good that you will be loosing the landing gear. We have been trying to figure a way go grade the unpaved part, but nothing short of hiring a tractor to drag it has surfaced. Big bouncy wheels sounds like a solution for the grass. They wouldn't help if you droped one in the holes at our field though.

Don

RE: Taking off on a bumpy grass field
 

Our club field is grass. Of course we roll it to keep it more-or-less smooth... But we do have a couple
of guys that love the big balloon tires made by trexler.
http://www.trexlerballoonwheel.com/ They seem to really smooth things out.

RE: Taking off on a bumpy grass field
 

Man, I haven't seen them in years, decades actually. I had some on a control line plane I built back in the mid 50's. If I remember correctly, they have a wood hub and the tire is basicly a ballon that you blow up as "hard" as you like for the conditions at hand, then just wrap the stem around the hub to seal it.

Some times the simple solution is the best.

Don

RE: Taking off on a bumpy grass field
 

Like he said, big wheels! And more power!!!

RE: Taking off on a bumpy grass field
 

Another big-wheel user here.
Our field has plenty of grass, lumps and bumps plus the occasional crater. The stock supplied ARF kit wheels (usually foam) get replaced by low-bounce rubber, upped a size or two. On takeoff, hold full up elevator at first, HOWEVER, ease off as soon as speed begins to build. This allows the plane to achieve the correct amount of lift for flight, while interacting with the turf as "gingerly" as possible. Also, make sure the wheels and landing gear are aligned and rolling freely. A trace of toe-in and a trace of positive camber can help if needed. Test roll your plane on a hard surface to confirm it will roll freely and track true. Every little bit helps on a grass field. Good Luck!

RE: Taking off on a bumpy grass field
 

find the flattest piece of field you can and apply power gently and pull the elovator up. once the plane wants to take off let the elovator go to centre and then pull back again

RE: Taking off on a bumpy grass field
 

I have the same problem here at my house. It's not terrible, but rough enough. My 3D planes are the easiest. Pull the flapperons down and elevator up and it's off. I can have my Funtana 100 and Frenzy 100 off the ground in about 10 feet.

RE: Taking off on a bumpy grass field
 

Yes that does seem to be the magic number doesn't it?

You gain going beyond this, but the transition from less than this to 3" or more is rather dramatic.

RE: Taking off on a bumpy grass field
 

I actually tried some 3 1/2" wheels but they had the flat edge instead of rounded and they provided much worse handlying than the 3" rounded type. I hit a gopher hole with 3" rounded tires on a 60 size Seafury and they were large enough to bounce over the hole and keep going rather than plough into it so that size works well enough for me. [8D]

RE: Taking off on a bumpy grass field
 

Unless they are too large, most any model airplane can be safely hand-launched, especially in any breeze.

RE: Taking off on a bumpy grass field
 

I'm not about to hand launch even a small .32 to .40 glow engine plane. My planes will last a fraction of a second this way.

Also how do I hand launch my .90's 1.20's .60's all of which are "not too large", let alone my 1.80 glows and my 50CC planes?

RE: Taking off on a bumpy grass field
 

Perhaps I should have inserted 'Trainer type Airplanes', but since this is a beginner forum, I didn't think it was necessary. I've nad no problems hand launching several types of airplanes, Sig LT40, Kadet Sr. (OS 48 Surpass), Ugly Stick etc, etc. Theres no way I would attempt any .90 to 50CC aerobatic model, Thats where the word LARGE came in.
Incidently,I've been involved with model aviation since 1950. Jim

RE: Taking off on a bumpy grass field
 

I've got another what if situation. My favorite field is undeveloped grassland, it get's rough cut from time to time, most of the time, the grass is rather tall, and losing a pack or motor in a crash means spending alot of time searching for them. I can't expect the owner of it to do anything more since I don't even know who owns it, nor does anybody care if I fly there, it's next to a housing complex.

I've been contemplating building a roll out landing strip, something I can just unroll, like a carpet, I wouldn't need much room for my little electrics, but would of course need more for the .40 fuel bird, of which the latter has not been flown there for obvious reasons.