Does the Hot Spot have the same bouncing problem of a Kangaroo?
How far behind the CG are the mains?
On the roo, the forward flange of the mains is the cg, so the wheels are less than an inch behind the cg.
I think this is part of the reason for the bounce problem.
I have tried slow landings, soft springs, lowered the AOA on the ground, you name it, I've tried it.
Still, when you least expect it, bam, it's bouncing like a ball again.
I'm thinking of switching to a Hot Spot if it would be an improvement.

I welcome any and all suggestions.

I used to bounce my Kangaroo until I figured out to bring it in nose high and touch the mains only on landing, let the nose settle in. After that I never bounced it anymore, just greased it in. I've seen hotspots bounce bad too, but they are heavier so they might stick better. Every jet I've flown, if I did not land mains first they would bounce, just my experience, but most tricycle gear airplanes I've flown will bounce if you 3 point them.

No bounce in Hotspot (unless you want[sm=wink.gif])

Yes, it will be a improvement.. but if you didn´t apply the technique cited by LGM graphix you will bounce any airplane.

I recently modified my old Roo to a lower thrust line setting and it is a fantastic flier...as good or better than the HS.. so perhaps that´s another option for you too.

Enrique

How about the CG location relative to the mains?
I would like to know where the CG is on the Hot Spot relative to the wheels.
I think that may be part of the reason the roo's bounce so bad.
The mains are almost on the CG.
If the mains were farther back, I think it would stay on the ground better.

Pete and I discussed this on Saturday at the feild. One question we had; is it possible to mix some sort of CROW in the Kangaroo, similar to what's used in Bobcats/Kingcats. I am not sure if it can be done with a plane with just Elevons?

I know the crow in my BC and KC works wonders...

The wheels are almost on the CG, like yours. and this helps to avoid bouncing if you land on the mains. If the mains where farther back, they could induce a nastier pitch down movement at the touchdown and make things much worse.

Sometimes Roos and HS are prone to hop if their CG are forward and the elevons don´t have enough movement. The plane´s nose simply fall off at the landing because there is not enough elevon authority at low speed. It bounces hard pitching up the nose of the plane while it
still has airspeed to fly (hop)... at this point, you are just a spectator.

About crow in the Roo and HS unfortunately it can´t be done. it is needed all the elevon surface to control the plane at low speeds...

Enrique

Hotspot lands very well.

http://www.zippyvideos.com/3270272264751116/hsland/

How about spring tension on the gear struts?
I'm thinking of cutting a few coils off to lessen the pressure, especially the nose gear.
May reduce the amount of rebound energy that keeps it bouncing?

Mine is nose heavy. but, If I lift the nose it will stay with the tail on the ground.
If I add about 16 ozs to the tail I can get it to balance on the CG.
May make the nose wheel kind of light for steering, although the high mounted engine does push the nose wheel down at full power.

Bob Parks once told me that problems like this could be solved by installing a trailing link nose gear with a shock absorber. He has a Roo, so you could ask him abuot it.

Enrique and Jeremy are right any airplane will bounce if you let it, with me Roo I knew about the problem and a had it happened too but I learned how to land it at a low airspeed ( with the help of some good friends ) and the bouncing went away completely.

This is my app. down wind, 1/4 th. hold altitude.
base leg, th. to idle half way to final, nose up and loosing altitude.
final leg, th. idle, nose up, if you need more speed hit the throttle just a bit for about 2 sec. then to idle, over the runway nose up a bit more and, very important, keep that nose up, don't let it drop at all, land with no bouncing, the ground effect will keep the airplane flying over the runway so keep the nose up 'till it land on the mains.

One thing, my apps. are short and high.

Hope this helps.

Yes, you can do it, and you can also add a small silicon cylinder at the end of the coil to have some
extra dampening.. about the nose heavy CG it is very common to happen in Roos, but it is not worth
to put extra weight on the rear. Just add a little more deflection on the elevons...(about 30 mm) and about 25% of expo that you will be able to hold the nose up in the landing for more time, getting rid
of the hops, like Carlos cited.


Enrique

Thanks for the ideas, I will give them a try this weekend.