Crow on a Super Balsa Bandit??
 

Ehab and I maidened my SBB this last weekend and what a great flyer!!

I could not believe how slow it could fly!!. IN-CRED-I-BLE!!

I landed without airbrake at a crawl[X(] with the P-70 at idle. I had my Bandit expert with me ;) and his help was very much appreciated. The airplane never seemed to "mush" on me but I had to feed some right rudder to make the strip and it suddenly tip stalled out of the sky with the right wing tip hitting first.[sm=75_75.gif] This cought us both by surprise. Ehab thought that I had given aileron causing the tip stall but as we all know rudder is the go to surface for correction on approach. Some damage to the gear but nothing too bad. I've already fixed her.

I mixed some crow into the ailerons for the next flight.

I reread the landing suggestions in the bvm instructions and I will make the following adjustments on my next landing

1. Airbrake on

2. 2-3 Degrees of glide slope (that's almost an imperceptable amount[:o]) I.e., keep the nose down.

3. Crow (about 1/2 an inch) on the ailerons

4. POWER BABY all. the. way. to. the. ground.


What do you guys think?? Thanks for the input.

Raf

RE: Crow on a Super Balsa Bandit??
 

Hi raf:

1/2" is probably too much on the aileron....May be a 1/8" and then a 1/4" will be a good point to start!!! I think BV does not recommend it, but we can try it at altitude!!!

RE: Crow on a Super Balsa Bandit??
 

The extra drag of the speedbrake allows you to keep the RPM a little higher on final, so the engine will accelerate to full thrust faster than from idle if you need to make a go-around. A fair amount of headwind cancels the need for the speedbrake.
"Crow" really improves the quality of my landings on my KingCat. No more floating right on bye.......round out at about a foot, and it greases right on....most of the time LOL.
"Crow" increases the sinkrate, by killing off the lift from the outboard wing, so don't forget to factor that in.
You will need to use more power with the "crow" and speedbrake deployed.


Harley Condra
BVM REP
JetCat REP

RE: Crow on a Super Balsa Bandit??
 

I was hoping that crow, by increasing effective washout, would decrease the incidence of my dumb thumbs to cause a tip stall. I realized that added power will be needed to compensate for sink rate but do you guys think it would make the nebulous "tip stall" less likely? Not only in any jet but in this one in particular?

Thanks again,

Raf

RE: Crow on a Super Balsa Bandit??
 

With it tip stalling the same way as the rudder, it would appear that you were close to the point of stall anyway and that the slower inboard wing stalled during the rudder turn?

Putting crow braking in will effectively reduce the angle of incidence of the outboard wing, making it more likely that the inboard section of the wing will stall before the outboard, effectively reducing the chances of a tip stall. However, if I understand the aerodynamics right, by reducing the angle of incidence outboard, you are effectively redistributing the lift to the inboard section but also slightly reducing the overall lift of the wing for the angle of attack of the aircraft overall. This will produce a slightly higher stall speed but with less risk of a tip stall, making for a slightly more benign landing characteristic.

You might also consider adding a wingfence, like on the BAe Hawk, as this creates a vortex on the upper surface of the wing which acts as a barrier - should the outboard section stall, the stall is less likely to spread inboard causing a full wing stall due to the vortex "barrier" caused by the wingfence. I believe that the reduction in lift from the wingfence is less than you would get than with the crow brakes, so your stall speed would be lower than Crow Brakes whilst still reducing the tip stall characteristics.

You can see the effect of the wingfence in the photo attached - the vortex it creates effectively destroys the lift on the wing behind it, i.e. the air pressure in that area is higher than across the rest of the upper wing surface - in the photo the high angle of incidence is creating massive lift and low pressure on the upper wing surface which is creating the water vapour that you can clearly see. You can then also clearly see the area where the lift is destroyed by the wing fence and the consequent "dip" in pressure along the wing. That's the barrier that prevents the stall from spreading inboard and causing the full wing stall. I think I got that right?!

Anyway, you may decide that the crow brakes will be less of a visual impairment than wing fences and a reasonably effective tradeoff between tip stall characteristic and overall stall speed. Your call!

cheers
Sheds

RE: Crow on a Super Balsa Bandit??
 

By the way, the other dips in the cloud outline (slightly further inboard and less pronounced) on that Hawk are likely to be from the buffet generators on the leading edge of the wing that look like white rectangles in the picture. They're like Toblerone boxes glued to the wing leading edge that create a buffet when the wing is close to the stall to give the pilot an indication that he's getting close!

RE: Crow on a Super Balsa Bandit??
 

I have a classic bandit and a super balsa bandit on the building board. The classic is an absolute darling to fly and land (hence buying the super bandit) with no hint of tip stall and it is a bit on the heavy side. I do a circuit on 1/3 power letting is slow down wack in take off flap again letting it settle then before the final turn into wind put full flap in keeping 1/3power on line it up LONG AND LOW approach as soon as you know its going to make the strip come off the power then if she looks to fast wack the airbrake in hold her off until she settles in - if you touch down before you ALMOST run out of elevator your going too fast.

And as for the adjustments for clam or stronger winds just keep the power on longer or come off earlier. Its the easiest plane to land I've ever flown its a darling.

Check the lateral balance

Thats how I land and I hope this help

All the best

Ant

RE: Crow on a Super Balsa Bandit??
 

Sheds,

Thanks for the learning material! I really enjoyed that pic as well, what a great shot of that hawk in the bank!:)

Ant,

I was under the impression that the SBB would be a darling to land! I should give her more of a chance. It was my very first landing with a bandit!!:D

I think I just got carried away with how slow it was flying. Wow!! I know I need power on the landing. I won't let my bandit expert talk me out of that again!!;):D You know who you are and I love you man!! HA HA!!:D

Just for S and G's I'll try a small amount of crow on my next flight and see!!

Raf

RE: Crow on a Super Balsa Bandit??
 

Raf: you can't listen to "some" of my instructions and then "ignore" others... It is a package deal (a GO FLY and LAND FURS Package:D:D). Expo rates were suggested but denied. Also, while it is not your fault, the flare happened too early and at a too high of an AOA (I have been repeating the landing in my head to figure out the problem). The Bandit, in a limited landing strip such as our club, is not very easy to land. You did very well for a first time Bandit landing and the damage is very very minimum!!! It will fly again......

RE: Crow on a Super Balsa Bandit??
 

Expo is incredibly important in jet flight, if you are not proficient in using expo, you need to get another airplane and learn it.

RE: Crow on a Super Balsa Bandit??
 

Ooooutch:(:(:(

RE: Crow on a Super Balsa Bandit??
 

rcumember, why don't you ask strawboss Dave Presta what he thinks about expo. Allow me to remind you that there is more than one way to skin a cat!!:D

I'll tell Presta that he is not profecient with a jet becuase he doesn't use expo!!:eek::D

Raf.

RE: Crow on a Super Balsa Bandit??
 

Dave has exponential thumbs.

RE: Crow on a Super Balsa Bandit??
 

So do I!![&:]