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Floats on CH701

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mcolbeck

Joined: 31 Dec 2006
Posts: 13
Location: Cochrane, Alberta

Posted: Tue Apr 24, 2007 4:18 am Post subject: Floats on CH701

Can anybody tell me what floats do to your gross weight? As it stands with extended range tanks (full), a passenger and myself we would be at gross weight. Is it a straight across the board change your landing gear to floats then redo your weight and balance?

I have not completed my aircraft but know that when I have completed my test phase I will probably switch from wheels to amphibs.

_________________
CH701 Builder and new flyer
Rudder, HS, and Elevator completed
Left wing Complete
50% complete on Right Wing
99% Complete on Fuselage
Engine installed almost ready to fire
Instrument panel and electrical Complete

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Tue Apr 24, 2007 5:29 am Post subject: Re: Floats on CH701

Depending on the float you use they generaly carry their own weight, so to speak. Meaning that if they way 100# they add additional lift of 100 #.



The only place this is a problem is if you are shooting for the LSA MGW and you are already at the MGW.

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

john.marzulli(at)gmail.co
Guest

Posted: Tue Apr 24, 2007 6:27 am Post subject: Floats on CH701

The LSA gross weight increases by 100lbs for floats to 1420.



-John in Seattle



On 4/24/07, Gig Giacona < wr.giacona(at)suddenlink.net (wr.giacona(at)suddenlink.net)> wrote:[quote]--> Zenith-List message posted by: "Gig Giacona" < wr.giacona(at)suddenlink.net (wr.giacona(at)suddenlink.net)>



Depending on the float you use they generaly carry their own weight, so to speak. Meaning that if they way 100# they add additional lift of 100 #. 



The only place this is a problem is if you are shooting for the LSA MGW and you are already at the MGW.



--------

W.R. &quot;Gig&quot; Giacona

601XL Under Construction

See my progress at  www.peoamerica.net/N601WR





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=108870#108870



 http://701Builder.blogspot.com/



"Flying a plane is no different than riding a bicycle... it's just a lot harder to put baseball cards in the spokes.

-Airplane The Movie  [quote][b]

billmileski

Joined: 07 Aug 2006
Posts: 68
Location: Ledyard, CT

Posted: Wed Apr 25, 2007 5:49 am Post subject: Re: Floats on CH701

I have often wondered about the "floats develop lift that counters their extra weight" thing.  Often when I see a 701 float installation, it looks like they are at a negative incidence with respect to the wing, so that when planing in proper trim, the wing is at some modest positive angle of attack for liftoff. In the oldest 701 installations it looks like the setup put the floats in a significant down angle (negative angle of attack) in flight, which looked to be developing negative lift if anything.  Anyone else have thoughts?



Bill Mileski

701 912S 89hrs

Avidmagnum

Joined: 18 Nov 2006
Posts: 19
Location: Wisconsin, Florida

Posted: Wed Apr 25, 2007 6:38 am Post subject: Re: Floats on CH701

I have a 701 on Czech 1200A floats.  The floats are set at a 3 degree down angle so that you can more easly rotate off the water.  I increased the gross weight by the difference in the weight of the removed gear and the new weight with the floats. (About 150 lbs on the 701) My gross is 1250 now. But please note at full gross it will not peform like a 701 on wheels!  There is more lift but also a lot more drag!  That's not to say it's a poor float plane ...it's a very good float plane but the lighter the better.  (Time for me to go on a diet!)  I had to do a lot of modifications to get it to cruse at 95mph (5500RPM) with a 912s. I often fly it at 80 to save gas.  

Tom Schulke   

100 + hours on floats (701)

650 + total floats

701 on floats (Czech 1200a)

Rans S-7 on wheels.... have Czech 1200A's on order

nyterminat(at)aol.com
Guest

Posted: Wed Apr 25, 2007 9:15 am Post subject: Floats on CH701

Tom,

    

   Ok let´s hear about the mods to get your cruise up.

    

   Bob Spudis 

   do not archive

    

  

    	  Quote: 	
		    (Time for me to go on a diet!)  I had 

to do a lot of modifications to get it to cruse at 95mph (5500RPM) with a 912s. 

I often fly it at 80 to save gas.  

Tom Schulke   

100 + hours on floats (701)

650 + total floats

701 on floats (Czech 1200a)

Rans S-7 on wheels.... have Czech 1200A's on order





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=109168#109168



rget=_blank>http://www.matronics.com/Navigator?Zenith-List

://forums.matronics.com



	


     AOL at AOL.com. 

    [quote][b]

Avidmagnum

Joined: 18 Nov 2006
Posts: 19
Location: Wisconsin, Florida

Posted: Thu Apr 26, 2007 5:57 am Post subject: Re: Floats on CH701

Ok Bob....The mods!



1)Skyshops retrofit kit w/ new cowling and Rotax air box....little help...but look nice



2)Skyshops kit for fairing out the lift struts....this was a big help!



3)Rans plastic cover for jury struts. did this the same time as the lift struts so who knows...but they look nice!



4)Made cover for the tunnel that the landing gear went.  This helped more in rate of climb.



5)The big one! Removed the slats and put on Vgs. Went from 85mph to 92mph at same prop pitch and with the less drag I was able to repitch the prop to pick up 3 more mph.  Flys better and stall went up only about 1 mph.   



This is what I did and it worked for me....  



Do not Archive



Tom Schulke

Stol 701sp on Czech 1200A Floats

912S warp drive prop

nyterminat(at)aol.com
Guest

Posted: Thu Apr 26, 2007 10:08 am Post subject: Floats on CH701

Thanks Tom, I will start with the stut fairings, already have the Skyshops cowl, You are right it does look good. Where did you end up putting the VG´s? Any pictures of the gear cover?

    

   Thanks again

    

   Bob

    

  

 --

Avidmagnum

Joined: 18 Nov 2006
Posts: 19
Location: Wisconsin, Florida

Posted: Thu Apr 26, 2007 12:11 pm Post subject: Re: Floats on CH701

Bob



The instructions are on www.stolspeed.com .  I like the VG's they sell and will buy a set for my Rans S 7 next fall when I go back to Florida.

For the 701 it's extra easy.  Just measure 130mm in front of the top  edge of the nose skin where it rivets onto the spar - this will be the front tip of the VG.  For under the horizontal stab measure 100mm in front of the gap between stab and elevator. I've posted the photo of the gap cover.  



Have Fun.



Tom Schulke

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cgbrt(at)mondenet.com
Guest

Posted: Sun Apr 29, 2007 4:08 am Post subject: Floats on CH701

Hi ,

I'm Canadian and built my 701 in 1994. Flew the test hrs on wheels then

switched to amphibs in 1995. The basic weight on wheels was 619 lbs, amphibs

increased to 760. The designed gross at that time was 960 lbs.

When I applied for the registration I  asked for an increase in gross to

1200, I included a lettre from Chris Hentz that approved the change but with

the warning of a proportional decrease in G loading and increase in stall

speed.

The 1200 gross was accepted by the Department of Transport.

Personally I do not believe that the floats develop lift. I base that on

their shape (more like an inverted airfoil) and their negative angle of

attack in relation to the wing. I have two front frames; one gives me a -8'

the other -4' relative to the wing. With -8' frame the cruise is 4 mph less

than the -4' frame. With the -8' frame lift-off occurs at 38 mph; with

the -4' it occurs at 42 mph.

Cruise speed is decreased approx 10 mph by the addition of amphibs. I

believe the difference is caused by negative lift and form drag . I would be

concerned about increasing gross without adjusting G limits.

Regards

Carl

701/912 amphibs.

ricklach

Joined: 20 Jun 2006
Posts: 127
Location: Kernville, Calif.

Posted: Mon Apr 30, 2007 7:30 am Post subject: Re: Floats on CH701

Hi Carl,



I would like to talk to you about getting a copy of the letter you provided with your request of a 1200LB weight limit. I will be applying for my registration to the FAA here in the U.S. soon and would like to do the same thing you did and the letter would help in my request.



I can be reached at:



rick(at)ravengear.us or 661-345-7755



Thanks 



Rick

cgbrt(at)mondenet.com
Guest

Posted: Sat May 12, 2007 3:55 am Post subject: Floats on CH701

Rick,

Here is Chris' letter. Sorry for the delay

Carl

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