Would a simple flap under the belly and in between the landing gear of some of my planes work somewhat to slow a too fast of a approuch which happens sometimes. Have only 6 channel and 4 non computer radios. Sig midstar with say a 3 by 4 inch flap with holes, deflected 45 degrees or less.Would it slow her down much. I do understand there will be elevator ajustment when deployed. thanks for any imput guys!!! KELLDOG

Yup. And if you ever build a Contender, you'll note the option to build in the same sort of flap. Not much of an airbrake, but it does give you lots of lift, you can slow to a crawl. Yes, you'll have to control pitch manually, with elevator, on your non-computer radios.

Best wishes,
Dave Olson

Have you exhausted the other option?

Full sized pilots soon learn that to steepen the landing approach you don't push the nose down. Instead you continue to hold a little back stick and reduce power. This works for our models as well.

Get the wing into a high lift and high drag attitude that is near the stall point but not near enough to induce wing drops and such and you'll be surprised at how steep the glide slope becomes. Pushing forward to sort of dive the model to the landing spot in a steep glide slope is the best way to ensure you overshoot or overstress the frame by pushing it onto the deck.

An airline pilot in my club used to preach this method and he was a masterful lander with some tough models. His trick was that the elevator trim was a main flight control. He would use it at least three times during a flight, once at takeoff, once while in the air to play at neutral and finally set it to a nice close to but not dangerously close to stall setting for landing.

And of course this should be practiced at least two mistakes high at first if you're not used to it....

I would look at which plane, which engine and which prop......

a bigger prop with a smaller pitch will slow nicely....

Thanks for your imput.Scar has the answer for me that it could work! Just want to kill some time this winter and try something that I have had in the back of my mind for years. I was AFRAID OF getting answers like bigger prop,lighter plane, change your approuch,use flaps,get a computer,etc. 747 pilots dont have flaps and all that because they cant fly! Flaps helps them. What really got me going was that p51 arf they claim is a trainer then remove the landing gear add ons and wing add ons its a regular hot sport flyer. I would like to do that with some simple settup BUT have it change in flight for slower landings or more. Question I have now is where abouts is the most appropriate place on the plane for the least amount of pitch change and yet have a large enough amount of surface area to be effective.On cg, in front or behind. I was thinking of in front, or on. Would also try this system on a king kobra with a jett 90 that is to say the least, slippery in the air. THANK YOU again, its a fun hobby!!! KELLDOG

If it's all for fun then great.

Something to consider. If you just need to make the plane so that it'll bleed off speed faster than the drag brake under the fuselage will work. But the model will still stall at the same airspeed and so it'll still be landing at the same airspeed as before. If you want it to actually fly slower then you need the extra lift provided by proper flaps that add both drag AND lift.

I also think you'll find that a longer and relatively narrow flap as you're proposing will require more of a deployment angle to get a decent amount of drag. How effective it is will be based on the amount of extra sq inches you add to the frontal area. You may want to consider making it so it comes down about 60 to 70 degrees and is long enough that it comes down to the tops of the landing gear wheels. That should let the brake be able to stay down for the whole landing.

And since it's not actually on the wing there may be some trim change but nothing like if it was actuallly part of the wing's airfoil so you'll likely find that you won't need much, if any, elevator trim.

I'm reminded of the late 70's vintage FAI F3B class gliders when they first started using ailerons. At that time they didn't use flaps but did put the nose canopy on a servo so it would come up like an alligator's mouth (is that the one that lifts up? Or is that the crocodile?) to add drag for the landing task. By all accounts they didn't do much and folks soon went on to flaps which gave them more options.

Be sure to come back with the findings be they positive or negative. It may just help out the next guy.

Bmatthews is absolutely correct. Adding a drag device will steepen the glide but since it doesn’t reduce stall speed, it won’t enable a slower approach. The technique he describes in his last comment is the most effective way to slow the approach.

Whatever you do, make sure that when you add this drag contraption, that the contraption itself doesn't weigh anything, or else you will be trying to land a heavier plane at a slower speed, which kind of goes against what I was taught about model aerodynamics.

If you ask me, the best quick fix is to bolt on a low pitched prop and learn to do steep approaches with a flaperon / elevator mix. Too forward of a CG will also make slow landings difficult or impossible.

Yea but, SOMETIMES my landing speed is much faster then my stall speed!!! Need a brake in the air, not lift. If the under belly flap helps out to slow her down to almost a stall speed it will be more then I was lokking for in this simple to use and make setup. PS. ITS NOT ALL FOR FUN!!! Am trying to learn from experence and wisdom from some of you old time modelers who I, and I hope many others tip our hats to. Just think, the next generation gets to learn about innovations from from,from, YES AAARRRRFFFFEEERRRRSSSS. So guess thats what I am wanting to do. Use conventional wisdom with out the computer radio. Love simplicity that is well executed in planes.After this project is accomplished this winter, will be moving on to my next one which is already in the works. OHHH BOY!!! You guys are going to love this one.Imagine this. Ceramic screens fitted on the end of your muffler that heat up and burn unburnt lubricant residue to keep your plane forever clean, AND give a free by nature a smoke trail. So far I found I need more heat from the muff. Could get it from a battery operated glow device I imagine on the screens. A engineer suggested a horse shoe type muff to restrict and generate more heat. By the end of the winter this sig midstar for sure will be like no other. KELLDOG

THAT'S IT SONNY! YOU GO WASH YOUR MOUTH OUT WITH SOAP RIGHT NOW! ! ! ! !



When I was flying my Quickie 500 with the 25 on it it was so clean that if I didn't set up the nose high mushy approach soon enough I had to go around. I soon learned to drive it down under speed and then out at the end of the runway pull up and into a very steep chandelle style of climbing turn and be sure that the recovery to level was done with some elevator trim added and to keep that nose up. The better I did that the steeper the approach. If something happened and the nose came down or I stalled it slightly and it sped up in the recovery it was go 'round time again. That thing held onto speed like nothing else. I've heard that the Formula One racers are even worse with their super clean profiles. They may be heavy but they are darned efficient.

This is true, but it only works if the C-of-G is reasonably correct. It is not an effective option if the model is somewhat nose heavy.

Have a sig kougar in my fleet also with a jett 50, turned into a tail dragger, built very very light and the cg is dead nuts. Have had this hot rod for 3 years now. NO!!!!!! I do not want to change the prop for slower landings. Leave the windmilling effect on my stinger 120 with a g 26. Just want to fool around and spend about 2 ounces to HELP SOMETIMES not over shooting the runway on a bad hair day. Going to do this, but was wondering from the start what size and where would be best. Going to try first on my trasher plane which is the midstar, a flap that is the width of the fuse and 4 inches deep inside the landing gear. Flaps I do understand should have holes to have more drag! Come to think of it! THATS what I want. Induced drag at a flip of a switch at a cost of 2 ounces with no computor or flaps. That alligator canopy is sounding awfully good!! Its in the ballpark anyways. My king kobra and kougar is what I really would like to slow down. Have slow and fast planes.These I want to keep fast In the air but not landing however. Is that why speed brakes where invented a long time ago? Thankyou again!!!!! KELLDOG