I've started this thread based on various discussions on and of line that I have about slowing down models that high glide speeds and very shallow glide angles ..

First that springs to mind - The HK racer series of 800mm -- Edge 540 and it's stable mate.

Debates range over inboard flaps, spoilers, spoilerons ... all good stuff but is that all ?

Lets set the scene :

A model that glides on and on ... speed decay is minimal and this leads to having to grease it in at higher speed than one would really want. It also creates problems in small field flying where you don't have distance to run in to let speed decay ... models small so distance out is also limited by virtue of seeing the model !
If you allow nose to drop - speed immediately increases .. if you pull nose up to slow her - she can easily flip over and BHAM.

The idea is to increase the sink-rate so glide distance is shorter, to get speed to reduce quicker so that sink-rate is allied to lower speed - but still keeping control of the model.

Suggestions please ... as intent is more to pass on many different solutions to people who may be having similar with their models ...

My first thoughts are to convert a small inboard portion of ailerons to downgoing flaps, at serious angle to increase dramatically drag outweighing any lift increase. Being inboard - they would not create a flip as if more outboard. Acting more like a downgoing airbrake. Leaving ailerons, elevators and rudder to keep her going.

Another guy is using Spoilerons dialed into existing set-up requiring no extra servos etc.

??

Nigel

If they have rudder and ailerons you could do a cross-controlled sideslip landing: http://www.pilotfriend.com/training/..._wing/slip.htm

Requires a fair bit of practice but in done properly will increase the sink rate significantly and get you much kudos from your flying buddies

Piper L-4 forward slip, landing and high tail taxi (0 min 45 sec)

Originally Posted by JetPlaneFlyer

If they have rudder and ailerons you could do a cross-controlled sideslip landing: http://www.pilotfriend.com/training/..._wing/slip.htm

Required a fair bit of practice but in cone properly will increase the sink rate significantly and get you much kudos from your flying buddies
.....

Have a terrible feeling that my Edge 540 wouldn't like side slipping in like that ! Nice if it did though !!

Nigel

The prop is a surprisingly effective airbrake if you let it windmill, or even add a tiny amount of throttle to keep it spinning at low speed. It won't drop the model to a dead halt in fifty yards, but it'll help eat up speed with no extra complexity or weird aerodynamic changes.

The best way to do it, really, is just to learn how the model flies. Figure out what speed it stalls at and then determine "what you can get away with" in terms of pushing up against that wall. You can circle around in a glide and bleed off speed while gradually pulling the nose up, and with practice you can get yourself lined up so that the end of this glide puts you right on the runway.

A bit of flaperon use can generally be used to increase lift for landing, but I've found that even the worst lead sleds can be slowed down pretty nicely if you just learn how to work them. I've got a 20", 9.5oz Depron wing that will FLOAT in and just plop in the grass as long as I manage its energy before settling into my final approach.

The Edge 540 racer that has prompted me to start this thread ....

The prop is small and it's braking effect when freewheeling or just idle throttle is minimal ... already gone that route ...
It's actually a route that I am not too fond of - I like to have prop actually creating a bit of propwash without increasing speed to help keep surfaces acting.

Bleeding of speed in turns ... yep - agreed but this baby has a nasty bite ! trying that in small area can cause her to flip on you so quick ... tried flat / near flat turns as well ... but that rudder is a big paddle ...

But all good stuff ... keep it coming ... (this is not just for the small wing, high loading Edge 540) ...

Anyone out there with comment / info about spoilers / spoilerons / flaps use and running in straight instead of turns etc. ? To add to the info ?
Like everything - there are plenty ways to skin a cat ...


Nigel

I like spoilerons, although on the model (Eflite Pogo) I have that most needs them, I've got only a single aileron servo

I've found them effective with small amounts on a low wing loading floaty trainer, and in a much larger dose on a moderately loaded but very slick warmliner.

Our club field has ugly approaches with a hill and trees precluding a long flat approach on one end, and a distant hill on the other that just makes models disappear during the base turn, so while I agree that learning the slow speed behaviour is important, a bit of a landing aid gives higher margins for error, and spoileron seems the easiest to implement.

On the gliders, I really like the spoilerons on throttle for reasonable direct glideslope control.

To slow a plane it need increased drag.

By carefully controlling elevator and throttle, if you can get the nose up to increase drag, and increase throttle to keep it flying safely, you can do a relatively slow landing.

I have done it on a few models as my flying site is rather tight for slippery models, plus I have to drop over some trees on the approach.

Basically a 3D model could almost land vertically, (tail first). By controlling the throttle and elevator, a high(ish) alpha landing is possible with many other models, (except maybe gliders, as opening the throttle doesn't seem to help if you haven't got a motor )

Obviously practice at a safe height, but get it right and it can help to slow a model down. Certainly worth trying.

I fly some heavy planes that want to land hot.
My F-105's wing loading is in the 40's and my Cougar is in the mid 30's. Very slick airframes to boot.
One trick I use is to add 3 - 4 clicks (beeps) of up trim to my elev on the downwind setting up my approach. The extra angle of attack (= drag) from the trim setting does the rest.
This is also how full scale pilots land.

Then...
I would use spoilerons instead of flaperons.
The Edge surely has more than enough wing area for some pretty slow flight.
Spoilerons would kill some of the lift it is making, needing even more angle of attack to stay flying, creating more drag.

The HK Edge 540 has a vicious stall if provoked, and the wing has a taper that can catch you out.

It can fly slow - but it's the time needed to get her slow from normal flight, she is like grease in the air - she flows on and on barely losing speed.

Drag is what is needed ... balanced so she stays level and just sinks / slows quicker.

Nigel

How would these go? Be the first in the club... http://www.hobbyking.com/hobbyking/s...lider%20spoile

Originally Posted by Grantham Kid

How would these go? Be the first in the club... http://www.hobbyking.com/hobbyking/s...lider%20spoile

Used similar back in the 80's but they were not self-powered ... needed separate servo.
Bit too long for my needs ... but they do work !

Nigel

I'm a big fan of dive/speed brakes that pop out of the sides or top of the fuselage. Not so much the ones that drop down and could get tangled up on landing... don't ask how I know. LOL!

But IMO, if yer gonna get dirty... get REALLY dirty!

Put dive brakes on the fuse plus a set of flaps, plus use transmitter mixing to give that "crow" deal where the ailerons go up as spoilers while the flaps drop down. That could be done with minimal effort and 3 little servos.

Full sized planes that can go Mach 2+ can get plenty dirty and slow down very nicely. No reason that our models can't do the same thing.

I have slipped some fairly heavily loaded models than had interesting stall characteristics. I would take that model up high and experiment with the slip before trying other mods.

It may do slips much better than the OP thinks. Certainly worth a try.

My clean and speedy LR-1A eF1 model slips great

The advantage of learning to slip and applying the technique to different models, with suitable tweaks of that technique as needed is that it requires no airframe mods or programming mods....

I found a video on that model, it didn't seem all that fast landing,...

...but flying.......

Hobby King Racer Edge 540 800mm (6 min 35 sec)

If you add flaps then use a Crow mix, flaps down ailerons up. Adds drag, kills lift and tames the stall characteristics. If not adding flaps then use Spoilerons, half of Crow.