Won't go airborne!!!

Won't go airborne!!!
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Won't go airborne!!! - 7/14/2003 7:18:19 AM

Posts: 8
Joined: 7/14/2003
From: Imperial, MO
Status: offline

Hello all. I have been a lurker here for a while and have a problem to ask about. I equipped my Flitecraft Solo with 33" Gee Bee floats, and it won't leave the water! I'm going to post some detailed pics below for your comments please. Here is my setup:

Flitecraft Solo:
- 36" Fuselage Length
- Weight: 6 lbs.
- O.S. .46 LA
- 11x6 or 10x7 Master Airscrew Prop
- 1 water rudder
- CG is a quarter inch forward of the front float leg

What I am experiencing:
- I am picking up some very high speeds on the water surface, but it won't lift off.
- At these high speeds the plane predominantly sits back on the rear half of the floats, creating a bit of a water loop.
- Forward of the step, water is splashing directly into the prop.
- I left air once for about five feet and it made an involuntary right roll back down into the water.

I obviously have an issue with catching too much drag from water on the floats. I may need the shorter 28" floats, or even a float that sits higher on the water. I have thought about filling the float half way with liquid expandable foam to improve the ballast.

Here are the pics, please let me know any suggestions you may have... I want to get airborne fast! Thanks!

Won't go airborne!!! - 7/14/2003 8:31:38 AM

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Joined: 4/10/2002
From: Edmonton, AB, CANADA
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you can CA or epoxy some plastic or 1/32 ply strips vertically on the inside edge of the floats (at the front) to keep some of the water spray out of the prop. When that happens, it really robs the power from the engine.

Judging from the pictures, the top of the floats appear to be parallel to the bottom of the wing. If you put a spacer, say 1/4" under the front strut to lift the nose up a bit, it will help the wing generate the lift needed to get off the water, and, as a side benefit, raise the prop up out of the water spray. There is some other stuff as well, but try the simple things first...

Both cross braces are bent. Make sure your floats are parallel to the fuselage.

Good luck

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Won't go airborne!!! - 7/14/2003 9:25:39 AM

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Joined: 7/14/2003
From: Imperial, MO
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[QUOTE]Originally posted by Nony
If you put a spacer, say 1/4" under the front strut to lift the nose up a bit, it will help the wing generate the lift needed to get off the water, and, as a side benefit, raise the prop up out of the water spray. [/QUOTE]

Why on earth didn't I think of that? Thanks! Keep giving me more suggestions please!

(in reply to Captain Solo)

Won't go airborne!!! - 7/14/2003 5:50:09 PM

Posts: 334
Joined: 6/15/2002
From: Gibraltar, MI, USA
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You said the plane does achieve high speed on the water and the floats are sitting on the rear half of the floats. At this stage, the rear half should be out of the water with the floats riding on the step. You didn't describe the surface of the water. If the surface was as smoothe as glass, you may have a problem breaking loose. Full scale float planes will have the same problem. I assume it's the surface tension of the water. One way to fix this is to taxi around creating some waves, then take off through them. You can also rock your ailerons a little to try to get one float at time to break loose. Did you recheck your CG after mounting your floats? You may need to rebalance. From the pics I wouldn't change the length, but I would go with a different brand. The step on the Gee Bee's is not square to the centerline which creates problems........Seaplane

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Won't go airborne!!! - 7/14/2003 6:34:30 PM

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Joined: 7/14/2003
From: Imperial, MO
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The CG is marked with the floats on. The water is smooth as glass, and I have no way to do anything but taxi a couple of wakes to break it up. Somebody said something in another thread about building up the step square by using epoxy. I'll have to look into your guys' suggestions. Please keep bringing on the help, Solo.

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Won't go airborne!!! - 7/15/2003 2:13:16 AM

FLYBOY

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Joined: 1/7/2002
From: Missoula, MT, USA
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The ply to the inside of the float leading edge is needed, and you also need to rough up the water. The floats are sticking to it. The reason it tipped when it did get off was it wasn't ready to fly. You might pick up some speed by adding just a touch of down elevator to get the back of the float out of the water and get it on the step. Then you can slowly lift it off and don't climb fast till you get speed up.

If the water is glass, it is harder to get it to go because it sticks. You can do a bunch of circles at high speed to rough it up and then go across them to unstick and get it to lift off.

Might also have a little power problem. I had one that did the same thing and just couldn't get off the water. Put a larger engine on it and it took right off.

Good luck. You will have fun when you get it going!

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Won't go airborne!!! - 7/15/2003 6:49:05 AM

4*60

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From: Blind Bay, BC, CANADA
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Isn't the step supposed to be at CG or 1/2 inch behind. This looks possibly ahead of CG which would help keep the rear of loats on the water at speed. Not what you want.

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Won't go airborne!!! - 7/15/2003 7:00:30 AM

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From: Cookeville, TN, USA
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I believe the floats are too far forward. My reference tells me the the effective step is the WIDEST point of the step when the floats have a tapered step like the GeeBee floats.

Also, the floats look to be larger than the traditional guideline of 75%-80% of the length from the prop to the rudder hinge. The only thing this really hurts is that the floats are heavier than they should be. Your floats look to be nearly the full fuselage length.

You also need to add some incidence to get the nose up. With the way your floats are mounted, make a 1" long mending plate from aluminum strip and add it to the front float mount. one hole in 1/4" from the end will bolt to the float, and one hole 1/2" higher will bolt to the existing hole in the struts.

SPray deflectors, as described earlier, help.

Initially, start your takeoff with full up elevator. This gets the nose up and helps the prop clear the spray. After a second or 2 the plane will pop up on the step. Relax elevator and let it accelerate. Then gently give it 1/4" back stick and it will lift off.

Personally I continue not to be a fan of GeeBee floats, and suggest that you get a good set of foam floats from one of the vendors listed in the FLFLFL website (below). OR from Plane Fun FLoats who participates in this forum as "seaplane". I keep promising myself I will post his link in the website, but still have not done it.

< Message edited by JimCasey -- Jul 15 2003 2:07AM >

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http://www.smilesandwags.com/Floats.html

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Won't go airborne!!! - 7/15/2003 6:53:42 PM

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Joined: 12/20/2002
From: Jasper, AL, USA
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quote:

OR from Plane Fun FLoats who participates in this forum as "seaplane". I keep promising myself I will post his link in the website, but still have not done it.

Isn't that site:

http://www.geocities.com/planefunfloats/

?

--Bill

(in reply to Captain Solo)

Won't go airborne!!! - 7/15/2003 8:35:49 PM

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Joined: 7/14/2003
From: Imperial, MO
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Yes, my floats are too long, but after the initial investment I'm going to try to make them work. Following you guys' advice I'm going to put a spacer on the front float mounts, move the floats an inch forward, and mount some spray deflectors on the floats.

One question, if I mount the deflectors off the top inside edge of the floats, how far should they stick out over the edge?

Thanks

(in reply to Captain Solo)

Won't go airborne!!! - 7/15/2003 9:44:21 PM

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From: Kingman, AZ, USA
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Captain I have been following your adventures with the Gee Bee's And I just would like to say that I agree with the other posters about you problems i.e. CG to far aft due to confusion over the less than adaquate 'v' shaped step and probably inadaquate float decaladge.

I only have one pair of Gee Bee's that were given to me that are about 27 inchs long. they have been successfully used on two RC ships and one controlline however on the first RC they did have a lot of sticking problems and I beleive totaly due to the poor step design. The solution on the second RC ship turned out to be carving simple triangle shaped balsa blocks epoxied to the bottom at the step to form a straight straight tranverse step and eliminate the 'v' shape. Also doing this it makes it possible to deepen the step a little so it is not so shallow. This allows for better venting of the after hull and minimise's sticking also. The shaping blocks are easy to make and after glueing to the bottom and sanding just apply a little glass over the wood portion.

Now the effect of installing these blocks will actually move the true step aft and coincide where you thought it was in the first place and your CG will be in the appropriate range. Doing this simple step and increasing the float decaledge a bit with front spacers, I beleve will make your ship quite flyable.

The only other possible problem is the front struts are pretty far aft on the aircraft and this will increase flexability some but that is not why you could not get off the water.

John

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Won't go airborne!!! - 7/16/2003 1:37:05 AM

4*60

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From: Blind Bay, BC, CANADA
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Please ignore.

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Won't go airborne!!! - 7/16/2003 2:29:59 AM

Posts: 8
Joined: 7/14/2003
From: Imperial, MO
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Here is an updated picture for you guys with a temporary spacer mounted between the fuse and float legs, and the floats moved back an inch.

I'm going to give it a test tonight to see if it performs better and if any additional improvement need to be made.

Next thing is installing the splash deflectors; if I mount them off the top inside edge of the floats, how far should they stick out over the edge?

Thanks!

(in reply to Captain Solo)

Won't go airborne!!! - 7/16/2003 3:39:26 AM

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From: Kingman, AZ, USA
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Whoa, forgive me Captain but in my opinion that is way to much, now the problem is the wing will be close to a stalled angle of attack when it leaves the water. Best way to use spacers is make a bunch out of 1/8ply and you can stack them to make adjustments. If it were me I would split the diff from that and what you had before.

John

< Message edited by JohnBuckner -- Jul 16 2003 2:31AM >

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Won't go airborne!!! - 7/16/2003 4:19:30 AM

Posts: 8
Joined: 7/14/2003
From: Imperial, MO
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Well, I guess it is pretty aggressive. I'll fart around with it tonight between the shop and the water to see how much to leave on there. Thanks for the great input!

(in reply to Captain Solo)

Won't go airborne!!! - 7/16/2003 6:01:36 AM

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From: Cookeville, TN, USA
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The good part about this is how much you are learning. Once they work, you are going to be so pleased.

And don't worry, we ALL did it the same way you have. Bought badly labeled floats, slapped them on the plane with inadequate instructions, and some of us got lucky and they worked somehow. A lot of us went through what you are going through. That's part of why a lot of guys think you need more power. With enough power, you can rip an anvil out of the water.

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http://www.smilesandwags.com/Floats.html

(in reply to Captain Solo)

Won't go airborne!!! - 7/16/2003 9:03:47 AM