aeajr

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This post was updated 9/18/2010

Many, perhaps most of the small electric planes can be hand launched. Many
don't even have landing gear. I take the landing gear off as it tends to grab
in the grass and flip the plane over on landing. I belly land all of mine.

Let's take a look at that hand launch as it can be troublesome for new flyers.

Always launch into the wind. ALWAYS!!!! No exceptions! If the wind is not
blowing into your face, you are facing the wrong way.

If you are flying an electric airplane, motor at FULL throttle. Remember, if you
throw-UP, that will make you sick. [X(] You want to send it straight out.

If you are flying an electric glider, you should be able to launch nicely at 1/2
throtte. Many electric gliders, like the Radian, will pull up sharply at full throttle.
And, they don't need a lot of throttle to fly.


Your plane may actually lose some altitude as it gains speed. As long as , the
wings are level and the plane is flat, that is fine. The plane should look
like it just flew past you, not like it is climbing, at least not right away.

Don't pull back on the elevator till it is up to speed. Maybe a TINY bit. It
should start to regain that altitude all on its own as the lift of the wing
kicks in. Until that happens, a big pull back on the elevator is like putting
on the brakes, and it will slow the plane down, the wings will lose lift and
it will stall and likely fall to one side or the other, especially if you
haven't thrown it with the wings level.


Stall?

Think of it this way, if you throw the plane up, it is like starting to ride
your bicycle up hill in high gear from a standing start. [] VERY HARD to do.
Better to start on level ground in a lower gear, get up some speed, then
attack the hill. Same for your plane.

If you throw up, the plane can not gain speed fast enough and the wing will
not get up to minimum flying speed. Getting a firm, flat, wings even throw
takes some work. Send it out like a big dart you are tossing at a board on the
wall.

Try this visualization:

Stand under the goal post of a football or soccer field. With the motor at
full power, throw it straight out so it will fly under the cross bar of the
other goal post.

Under the other goal post? Yes under!

That should give you a nice flat throw! If you are trying to throw it OVER the
goal post, you are tipped up too much. Strong firm, flat throw, not up, or
only slightly up. Those wings need to be flat to gain lift. ( Don't worry,
by time it reaches the other end of the field it will be much higher than
that cross bar, but don't try to throw it over the bar. Let the plane do it.)

This tendency to throw up is a very common mistake that lots of new flyers
make. You will crash and crash and crash and that will just make you sick! [&o]

Remember: If you throw-up, it will make you sick!

I recently exchanged messages with a new pilot. He was having
terrible problems. Happens that he lives near me. Brought the plane to me.

After checking it out, I launched the plane. The plane flew perfectly. In fact
I set it at full throttle, threw the plane and then stretched my arms out wide
so he could see I was not touching the controls.

Turned out he was throwing UP at about a 45 degree angle. Now he does it
right, flies in 10+ mph winds and is teaching his brother how to fly. [8D] He also
became a member of our club.

So, is your hand launch making you sick?

aeajr

My Feedback: (2)

No responses? Interesting. This is getting a lot of action on other forums.

CoarseAir

FWIW.... I read on another forum where many Parkzone P-51s were rolling left and crashing into the ground immediately after a level hand launch at full throttle. After much discussion, even Parkzone admitted that even tho the instructions stated "full throttle", tech support amended that to "about half throttle to a little more than half. Seems to much torque at full throttle was the culprit.

My $.02.

aeajr

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Thanks for adding to the thread with that useful information.

Leo L

I know that I'm in the minority on this, but I find ground take-offs much easier than hand launches.
When you ground launch, you are in complete control from the time that you first apply power till the plane is flying. With hand-launches, either you rely on someone else to give you a proper launch, or you launch it yourself and then scramble to get a hold of the controls to keep the plane flying level, straight and at the desired speed.

I know that a number of flyers and some manufacturers claim that you sacrifice a lot of battery time perfoming a ground take-off. This doesn't make sense. If you perform a proper take-off, the plane will be airborne in less than 5 seconds, at which time you can cut the throttle from full. 5 seconds of WOT does not seem like it will impact the power curve of the battery to any noticeable extent.

Of course one of the drawbacks with ground take-offs is that you need a relatively hard, relatively smooth surface for the runway: most RTFs will not taxi on grass.

aeajr

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Ground take-offs are great and I don't think you sacrifice much if any battery life, but you do need a "runway of some kind. I don't have a runway, so I remove the landing gear and just hand launch and belly land everything.

Barwelle

I agree with aeajr with hand launches instead of take-offs, but merely because I, also, do not have much of a runway. I live on a farm, and you'd think that i have lots of flat land to take off from... but actually, all of the land is way to rough to take off from for a parkflyer and some smaller glow planes. there's just much less risk with hand launches (if you do it right, of course) than taking off, because you're not bouncing around the bumps while the plane is speeding up. taking the gear right off is another good idea because trying to land with gear... if you have a taildragger, the front wheels could catch and flip the plane over, and with a tricycle gear, the nose wheel could dig in and flip or spin the plane around. I know that there's not alot of farmers but I'm sure the same condition goes for alot of places, the only place I would want to use gear is If I have an empty parking lot, because of the hard, smooth pavement. As long as you cut the throttle before you land, so that you don't ruin the prop or possibly damage the rest of the plane, no gear should be great.

Hatty

What do you do for the prop with a belly landing? I know that you can buy a folding prop to keep from screwing it up, but on my plane, the cowling is too close to the prop for it to fold. Thats why I always use a runway to fly. Also, doesnt a belly landing scratch your plane up? I would rather the landing gear take the punishment than the belly of the plane. My 2 cents.

aeajr

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so far a smooth landing has never broken a prop if the motor is off. However I have recently stated using "prop savers" that mount the prop using a rubberband so it can give on impact.

Scratch up? Not a real problem on grass. I also fly a 3.8M scale sailplane and I belly land that too.

As far as landing gear taking the punishment, when you land a light model on grass, what happens is the landing gear just hangs in the grass which can slam the nose of the model into the grass. This is the only way I have broken anything on a good landing. In fact I have flipped the plane, due to the landing gear and broken the tail.

Net net, I take the gear off on these electric planes that are under 2 pounds.

balsabuster2003

A fellow clubmember avoids the torque-roll launch problem by hand launching like this: (Pictures taken by Dieter Mahlein. To see more pictures taken at the Equinox event, click on www.shredair.com , then click on 2005 Equinox Electrics.)

aeajr

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If you don't have a runway, this discussion, while old, should be helpful.

Flypaper 2

I fling mine with the wings leaning to the right a bit. The black O rings don't last to long so I bought slingshot rubber from Wallmart. Slice it into doughnuts. Depending how strong you want them governed by the length. Smaller,15 in. wingspan planes, about 1/8 in long. 25/30 in. span about 1/4 in. long. Lifetime supply, almost.

cyclops2

If I like a clean lightweight plane. I leave off all landing gear. I enjoy GWS & my scratch builts flying clean & put them into the grass with a tail dragging stall 6" above the weeds or grass.

A-10 & the Clipper are hand launched easily at 1 pound / sq. ft. of W L.

All the nitro landing geared planes have 2 X the engine size recomended. So I just vertical launch them while holding the plane over my head.

BigTb17

Most of my planes have been a breeze to hand launch. I also agree that a gentle belly landing has generally been easy and effective.

My Mini Delta has been the only plane that has been tricky. The first several launches it simply glided away beautifully and with no problem. Then all of a sudden it started standing straight up right in front of my face and stalling when I tossed it. I found that if I made a conscious effort to throw it level I didn't have any problems. On the other side of the coin, my buddy throws his Stryker almost straight up. I questioned why he throws it so straight up and he said he didn't have any luck throwing it level. I never saw him try throwing it level, so I don't know what happened. But whatever, it seems to work for him.

I will say that I enjoy ground takeoffs. You do feel much more in control because your hands never leave the sticks. It's also just fun for some reason. It definitely seems more scale. Plus there is just something about taking off, flying and then landing that feels satisfying.

cyclops2

Tb17

I have a small original scratch built delta that looks like the Saab Draken J 35.

I screwed up on the COG & the Center Of Pressure locations.

Same problem, slow speed LEVEL is fine. I moved the cog around & can not get a happy point........[&o]

Deltas can be a handfull, if poor.....guessing.....scratch built.

Rich

aeajr

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Rich,

Is there a question in there somewhere?

baron2010

I'm glad to see this post..as I'm getting my 1st rc plane today, the avion io, and
was wondering about proper hand launch...hopefully I'll remember some of these
tips when I get excited about my first ever rc flight!!
thanks
don

[email protected]

Is a baseball infield, the dirt part, suitable for ground take off? I

aeajr

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Could be. Depends on how smooth the ground is, how high the infield grass is and how well you can keep it in the base line.

whitecrest

I prefer hand launching and also like to use the landing gear for landing. The flat-launching technique works very well for me. Also, I have found that using a neck strap for the transmitter helps a great deal with the hand launch. It lets me easily one-hand the motor throttle up just before the throw. My models are somewhat over powered, so I rarely need full throttle for more than adequate takeoff thrust. I have not experienced any problems with torque rolling during launch. I am wary of changeable wind conditions on the field that could possibly result in a launch that is not directly into the wind.

I have had good luck using the GWS type, thin, suspension 2.5" wheels and 1/16" inch wire for planes weighing about 19 oz. This landing gear is practically invisible aerodynamically (and visually once airborne). I use a beefy torsion block to anchor the gear in the plane, and this has never failed despite some fairly hard landings. I place the landing gear well forward of the wing leading edge which helps a great deal to avoid tipping. I like the extra protection the gear provides for the propeller in addition to that provided by the prop saver.

I usually fly at a local complex of soccer and baseball fields, and the grass is usually about 2" high. Generally, the plane with stay on the wheels unless it finds an area where the grass is very long. If it does tip, it is usually for just a second and very gently before it's back on the wheels. Usually, during the summer, a few browned out areas appear on the field, and landing there on the wheels is usually routine.
I avoid landing on or taking off from baseball infields or the dirt track because I have had pyrite sand particles attracted into motors.

aeajr

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If you have enough runway, and it is smooth enough, ROG, rise off ground is probably the safer launching method. But, as stateded earlier, some of us don't have any kind of rundway area. When you fly in a big open field with grass that is cut to about 2 inches, it is just impossible to get a plane like a Sky Fly, an Aerobird, A SmoothE or similar parkflyer to take-off from the ground. And many parkflyers don't have wheels. The Easy Star and the Radian are two good examples.

So, for those who must hand launch, and for those who prefer to hand launch, Hopefully this thread will have some value.

aeajr

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Let's bump this to the top to help the new pilots.  I just updated the first post to remove broken links and update some of the info.

Leisure_Shoot

I'm surprised at the number of folks who seem to have trouble with hand launching, other than planes with issues like the above-mentioned Mustangs.
I have been teaching myself to fly since July, in my backyard. My first flight ever was hand launch.
The only issue I can imagine is folks thinking they need to throw it "up" at a 30 degree angle.
I do launch my plane with a slight up angle - maybe 10 degrees? Seems to work very well.

aeajr

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Let's bring this to the top for all those new pilots who can't understand why their plane crashes on take-off or from a hand launch.