Skidding with the Savannah XL

[zhoser]

Hello

 

After flying 10 hours my new Savannah XL I am very happy with it but I have one concern about the brakes:

 

I have noticed in some sand runways I have skidded to the left and right after I pushed the feet brakes I think not very strong and not very quick (30-40 mph aprox), I was a little concerned about this because I felt I could have gone out of the runway, I suppose these feet brakes are very powerful if you compare with the hand brakes most of the ultralights usually have. I suspect I need to use them more softly, anyway I have always used the brakes hard in all my planes and I have never skidded a plane before.

 

I think the Savannah has to be nearly stopped to push the brakes in a sand runway but I see it a problem in a short runway If I can´t use the brakes from the first moment I am rolling over the runway.

 

I´ve thinking to change the feet brakes to a hand device to brake to both wheels and not differential brakes like the Savannah has.

 

Now I am a little afraid to push the brakes in a sand runway and I try to wait until the plane is nearly stopped but this way to land I don´t like when the runway is short.

 

¿Do you have some advice?, ¿Am I doing something wrong?, ¿has anybody had the same problem?

 

Regards

 

Carlos

 

 

[ozbear]

Carlos try retracting your flaps b4 hitting the brakes the extra weight on the mains might help

 

 

[Osteri]

I did not like the toe brakes and I made a change in my ICP Bingo 4S VG. I installed one of the original master cylinder and modifying the handbrake

 

 

[Osteri]

 

 

 

[facthunter]

There are definite advantages in keeping them differential. Ultralight aircraft don't usually rely on harsh/strong braking and their brakes are often somewhat minimal. Keep the weight on the wheels but with high lift wings and slow stall speeds that's not as easy as it may seem. Some people manage to put T/W on their nose with brakes, but with minimum care and training that shouldn't happen. If you skid be quick to release if directional control is a problem. Nev

 

 

[eightyknots]

Braking is most effective at the point where the wheels are still rotating, but only just. ABS (automatic braking systems) in cars work on this principle. So, the most straightforward solution seems to be to brake more softly so it just doesn't skid to get the minimum stopping distance.

 

 

[facthunter]

Well that is certainly true. Most aircraft have ABS and would blow tyres very easily without it. They also plant the weight of the plane on the wheels with spoilers to destroy lift. Judging the amount of braking force with circumstances changing constantly isn't easy. Releasing and re-applying the brakes may be one method which I suggest you try, if you have a directional control problem. Aquaplaning is a similar thing, but involves high speed and water on the runway. Nev

 

 

[Kyle Communications]

Carlos

 

I can tell you exactly what is happening. It happened on my XL as well. I have since modified my brakes to suit. But essentially you are landing too fast the aircraft is still flying and is too light on is wheels.

 

Read this thread it has a lot of info in it about my aircrafts incident and even some video

 

http://www.recreationalflying.com/threads/savannah-incident-at-caboolture.67974/

 

 

[markendee]

Howdy Carlos,

 

Could it be you have brake fluid instead of ATF in the brake lines?

 

Brake fluid makes them very severe.

 

500 hours in my Savvy and I love the toe brakes - wouldn't change them for quids.

 

 

[rankamateur]

wouldn't change them for quids.

Good to see you back Mark.

 

 

[Ultralights]

practice braking more softly, and also, dont forget, even at 40Mph, the fat wing will still be producing lift, enough so that the weight on wheels might be considerably less that you think, leading to skidding.

 

 

[Yenn]

Why use the brakes? You must be going into very short runways if you need hard braking in a Savvy.

 

 

[eightyknots]

Why use the brakes? You must be going into very short runways if you need hard braking in a Savvy.

...or, perhaps the landing spot is a bit downhill?

 

 

[dan tonner]

[ATTACH=full]39665[/ATTACH] [ATTACH=full]39666[/ATTACH]

Hello Osteri;

I'd love to see more details of your handbrake modification and a summary of your level of satisfaction with it. I have a Savannah XLVG and can't quite get comfortable with the toe brakes.

 

In your photo I believe I see a Park Brake built in as part of the mechanism - is this correct? Do you have drawings and details you'd be willing to share?

 

Best regards, fly safely,

 

Canada Dan

 

 

[Osteri]

I like use hand brake. I do not need a differential brakes.

 

Yes, the parking brake is included in the structure. I actually designed it. Can you send your e-mail address to "roste (X) kotinet.com" I'll send you drawnings. I will take more photos.

 

 

[Kyle Communications]

My Sav has been just with the brakes since I made the modification to the rudder pedals.

 

http://www.recreationalflying.com/threads/another-new-savannah-xl-on-its-way.10493/page-38

 

The originals are way too small for my big feet and also others who have flown the plane. By making the pedals longer I get more mechanical advantage so now I only have to squeeze the pedals instead of pushing them and I am using the ball of my feet not the underneath as before. With the brakes on top in this new format I get better control and pressure on them. The extending of the pedals makes a huge difference and of course I still get the differential braking and the advantages of the same.

 

 

[JerzyGeorge]

HelloAfter flying 10 hours my new Savannah XL I am very happy with it but I have one concern about the brakes:

 

I have noticed in some sand runways I have skidded to the left and right after I pushed the feet brakes I think not very strong and not very quick (30-40 mph aprox), I was a little concerned about this because I felt I could have gone out of the runway, I suppose these feet brakes are very powerful if you compare with the hand brakes most of the ultralights usually have. I suspect I need to use them more softly, anyway I have always used the brakes hard in all my planes and I have never skidded a plane before.

 

I think the Savannah has to be nearly stopped to push the brakes in a sand runway but I see it a problem in a short runway If I can´t use the brakes from the first moment I am rolling over the runway.

 

I´ve thinking to change the feet brakes to a hand device to brake to both wheels and not differential brakes like the Savannah has.

 

Now I am a little afraid to push the brakes in a sand runway and I try to wait until the plane is nearly stopped but this way to land I don´t like when the runway is short.

 

¿Do you have some advice?, ¿Am I doing something wrong?, ¿has anybody had the same problem?

 

Regards

 

Carlos

Hi Carlos,

Differential brakes are wonderful, I have 500 hours on Savannah and would not change to hand brakes.

 

Make sure that you have even tyre pressure on main wheels. And landing on soft sand. wet grass or loose gravel it is possible that one wheel or the other will present higher rolling resistance , happened to me a few times and this is the moment when differential brakes are worth gold you can straighten rolling direction with your feet activating brakes like tap dancing or ABS in your car . Have to be pretty quick with your feet and do not wait fully for the results , do not overdo it . the best way is to practice on grass strip in lower speed and get the feel for it. I have fairly large rudder pedals ( like a drilled aluminium pedals for race car) with toe brakes on the top. My advice is do not convert to hand brake learn how to take advantage of toe brakes, keep tyre pressure the same ( left=right). Happy flying