Nosing over

[sruelle]

In our last discussion with Len, we were sharing our pain in regard nosing over when you take off with a SLS.

THE solution is to have a glider with a nose wheel like Duo Discus, DG500. But when you have a single seat, it is not the case.

An other solution is to program the slope of the speed controller to ramp slowly to avoid this. Easy on a paved run away, on a grass strip it usually lead us to have more than one attempt to really take of, consuming some precious Watt out of the battery!

Also the smaller you glider is, the bigger the problem is. It can run OK for 1/3 scale or up but for 1/4 scale.... thats really not efficient!

My way is to use a bungee with a hook to gain the precious speed allowing you to be airborne quickly.

What you need :

- 10 yard of a recycled high start, or some fresh one if you don't have any.

- 2 yard of mason line

- A welded ring

- Some piano wire

First step is to manufacture a hook using some piano wire, 2mm is far enough.

Bent it as a Z end like to connect to a control horn. on the other side put the shape like a rectangle to increase surface for gluing it to the bottom of the fuselage.

Then Drill a hole a little bit larger than the piano wire in the bottom of the fuse around 1/4 distance from nose to leading edge from the nose.

Glue the piano wire at the bottom of the fuse, bending it slightly to have the hook retracted during flight. You will then need to pull it out to connect it to the bungee. Of course add some fiberglass to stiffer the area.






Then the bungee,

I use a dog anchor screw on one side connected to the bungee, and the 2 yard of mason line with the ring are on the side of the glider.

Connection on the bungee can be done using cable ties


If you have selected a proper quality of latex tubing you can stretch it 3 time the initial length.

So game plan is getting the bungee in position, getting the glider ready, stretching the line. Then holding the glider by the fin, setting the sls full speed and release it to be airborne in 2 seconds.

Ring will fall of sooner or later

Be careful, it it like aerotow, set you elevator to slow rate as you have the speed of the bungee plus the full air flow of you SLS on you elevator; making it really sensitive.

Hope it help

Stéphane

[sruelle]

Here is a small video took last year at our spring aerotow



Stéphane

[Len]

Stephane,
Thats a great idea, Maybe you can take a few more minutes and bend up a piece of metal and get some pictures posted to be a little clearer. I am going to do this on the Shark ASAP.

LEN

[Harm]

To make a nicely removable bungee hook you can make one which fits tightly onto your towing mechanism and is held by the closed mechanism.


In order to lessen the tendency to nose over here are some, more or less obvious, tips:

- Make sure your main wheel turns with minimum resistance;

-The larger the wheel the lesser the resistance;

- When the retract or fixed main wheel hasn't been fitted yet, consider to position it further forward in the fuselage;

- Tilting the SLS somewhat backwards lessens the tendency to nose over (probably because of more pressure on the stabiliser).

[sruelle]

Len,

Here is couple picture that should be self explanatory for the hook design





the ruler is in inches


Harm,

You are right 100%, wheel was not spinning freely and in the design I did end up putting 15° sweep backward, but it has not solved the problem to my taste

For joining the hook to the landing gear, it is pretty slick but it has to be really well designed to not interfere with the retract operations.

Stéphane

[Len]

Stephane,
You are the man,

Thanks for the clarification.

LEN

[Harm]

Stéphane,

I didn't say to hook up the bungee hook to the landing gear but to the air tow mechanism. Depending on the construction you even can try a split last second emergency release when the bungee connection doesn't release.

[sruelle]

Harm, I Miss understood

I have already seen a hook on the landing gear. Work well, way far too much job then to have the landing gear retracting properly with the door for me.

Using the tow hook can be an easier solution (not needing any other hook) as you said. I have seen that once but was not comfortable using it.

Do you still have the DG that you were flying @ the WE organized by D. Bely in 2005? DG600 if I remember correctly. Very impressive and stiff in flight


Stéphane

[Harm]

Stéphane,

Here is a link to an old thread on RC-network where an example is shown of a removable bungee hook attachable to the tow mechanism.
( contribution 18: http://www.rc-network.de/forum/showt...chleppkupplung )


Off topic: I'm not sure which of my two DG600's I flew in France in 2005. It could have been the 4.8 meter H-Model DG600 or the 6 meter RiPo DG600 Evo. The first one I sold with major damage after a crash. The second one ist still standing around damaged after a wingtip was severed at Middle Wallop (England) 1.5 years ago. While being towed I was dragged into a vintage model glider, causing major damage to both gliders (both landed safely though).
I still have two tow meetings every year with Dominique at Pardines, I love the meetings in France.

[sruelle]

Harm,

Just a word : SMART! Real nice idea

I have seen one using the tow hook directly, but using it this way is really safer!

Off topic : That was the Ripo! Too bad to have damaged this one, Ripo is for me the top of the notch Brand!

Stéphane