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May 29, 2020, 09:10 AM
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mntgab's Avatar
I figured out my Ch#1 issue. Rx is ok, for some reason the model program got corrupted. I deleted the model and re-created it and now it's fine. Has anyone seen this before?
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May 29, 2020, 10:46 PM
Registered User
Quote:
Kevin, before trying any curve, use the subtrim or center position (ppm center) to place the one flap at the same position as the other.
Newbie question. I see ppm centre mentioned repeatedly through these 90 pages.

What does ppm stand for and where is it?

Thanks
May 30, 2020, 09:39 AM
Registered User
Quote:
Originally Posted by claussen
Okay, now I'm stumped.
I've been flying three different models on this setup (each configured per the instructions), but I'm not finding a way get enough up aileron travel with flaps full down, particularly on the planes that have the most down flap travel.

When I have ~50-60 degrees down flap, my ailerons don't reach level with full stick, leading to reduced roll control -- if I set them up to be level at full stick, I don't get full flap.

I don't see anything in the existing mixes that I could tweak to help rectify this, but it seems kind of fundamental that you'd want the ailerons to go full flat with full stick when the flaps are down.

I've been screwing around with adding mixes to try and correct this, but not having a lot of luck.

Has anyone else found clever workarounds for this, or am I missing something in the original setup? AFAICT I've done everything by the book during setup, with slider all the way up and in cruise mode, in the proper order, etc.
RC newbie here. So take this for what it’s worth.

Airliners have the same issue. The more flap you extend the less roll control you have. It is why jets have spoilerons. Basically ground spoilers that become active at low speed in landing configuration. They help drop the wing. I’m pretty sure we can’t put spoilerons on our gliders though. Just mentioned it to point out it is normal.

One of the other things we do to increase roll control is land with less flap particularly in gusty conditions.

When you extend flap initially it is mostly lift and very little drag. The more flap you extend, drag increases exponentially but lift does not. In the deep flap range of 50-60% you are producing very little extra lift than at say half that deflection. Just way more drag. Not saying drag can’t be useful just that in that range it doesn’t help you fly much slower and has roll control issues.

Have you considered playing around with simply using less flap during approach? You should be able to approach at basically the same speed at say 25-35 degrees. On windier/ gusty days use even less flap. Ground speed won’t be an issue into wind with a slight airspeed increase but it will increase roll control in the turbulence.

Energy management would be different. However none of this stops you from using full flap when the drag is required.

This is how I have been operating my glider with Adrian’s program and haven’t had any issues with roll. I do have the issues you describe at full flap so I don’t get close to the ground with that much flap out.

I have found the sweet spot for my glider is about half throttle stick. No alteration to the programming required. Works great.

Overly aggressive rudder deflection close to the stall speed can lead to one wing stalling. When using yaw to turn you are accelerating the wing you want to rise and decelerating the wing you want to drop. If the decelerated wing stalls you will end up on your back.

Thanks again Adrian. Great program. I am getting a lot of enjoyment out of my glider. Vast improvement during quarantine

Problem is now I want a better one!
Last edited by Dan McSweeney; May 30, 2020 at 09:54 AM.
Jun 01, 2020, 08:42 AM
Jesper Frickmann
jfrickmann's Avatar
Quote:
Originally Posted by claussen
Okay, now I'm stumped.
I've been flying three different models on this setup (each configured per the instructions), but I'm not finding a way get enough up aileron travel with flaps full down, particularly on the planes that have the most down flap travel.

When I have ~50-60 degrees down flap, my ailerons don't reach level with full stick, leading to reduced roll control -- if I set them up to be level at full stick, I don't get full flap.

I don't see anything in the existing mixes that I could tweak to help rectify this, but it seems kind of fundamental that you'd want the ailerons to go full flat with full stick when the flaps are down.

I've been screwing around with adding mixes to try and correct this, but not having a lot of luck.

Has anyone else found clever workarounds for this, or am I missing something in the original setup? AFAICT I've done everything by the book during setup, with slider all the way up and in cruise mode, in the proper order, etc.
Please check out my SoarOTX program (F3K, not "F3K traditional"), it gives you full aileron control by "bumping up" the flaps if needed.
https://github.com/jfrickmann/SoarOTX/wiki

Jesper
Jun 01, 2020, 11:03 AM
Registered User
Quote:
Originally Posted by Dan McSweeney
Newbie question. I see ppm centre mentioned repeatedly through these 90 pages.

What does ppm stand for and where is it?

Thanks
Disregard. Found it.
Jun 06, 2020, 02:25 AM
A different attitude to RC
extremewing's Avatar
Thread OP
Great writeup. I will reduce the flaps, use the ailerons to correct roll, then pull flaps back on. You get good at that. Full flaps at high speed makes the glider stand on its nose just about. Its fun. If the flaps to elevator mix is well configured, this works even better.

Quote:
Originally Posted by Dan McSweeney
RC newbie here. So take this for what itís worth.

Airliners have the same issue. The more flap you extend the less roll control you have. It is why jets have spoilerons. Basically ground spoilers that become active at low speed in landing configuration. They help drop the wing. Iím pretty sure we canít put spoilerons on our gliders though. Just mentioned it to point out it is normal.

One of the other things we do to increase roll control is land with less flap particularly in gusty conditions.

When you extend flap initially it is mostly lift and very little drag. The more flap you extend, drag increases exponentially but lift does not. In the deep flap range of 50-60% you are producing very little extra lift than at say half that deflection. Just way more drag. Not saying drag canít be useful just that in that range it doesnít help you fly much slower and has roll control issues.

Have you considered playing around with simply using less flap during approach? You should be able to approach at basically the same speed at say 25-35 degrees. On windier/ gusty days use even less flap. Ground speed wonít be an issue into wind with a slight airspeed increase but it will increase roll control in the turbulence.

Energy management would be different. However none of this stops you from using full flap when the drag is required.

This is how I have been operating my glider with Adrianís program and havenít had any issues with roll. I do have the issues you describe at full flap so I donít get close to the ground with that much flap out.

I have found the sweet spot for my glider is about half throttle stick. No alteration to the programming required. Works great.

Overly aggressive rudder deflection close to the stall speed can lead to one wing stalling. When using yaw to turn you are accelerating the wing you want to rise and decelerating the wing you want to drop. If the decelerated wing stalls you will end up on your back.

Thanks again Adrian. Great program. I am getting a lot of enjoyment out of my glider. Vast improvement during quarantine

Problem is now I want a better one!
Jun 06, 2020, 10:14 AM
solastagia
kcaldwel's Avatar
I've modified the program to have 100% differential, and a lot more aileron throw in my landing mode. I have excellent roll control at any flap deflection now.

Taking flap off to correct roll may work, but it really isn't what I want to have to do. It is an unnecessary complication to the pilot workload during landing approach, and can be avoided if the ailerons are set up to work properly with flap deflection in the program.

Kevin


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