Canadian Flag Blowing In The Wind Ron Leclerc Zenith CH701 Construction Log


Zenair CH701 STOL Aircraft...
CH701 STOL

Winnipeg

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CH701 Float Design:   1 | 2 | 3 | 4 |    Next...
 

 
CH701 Amphibious Floats Design and Construction...

 
 
I must say that designing Amphibious Floats for my CH701 proved to be quite an interesting desirable project... lots of unexpected challenges, but not anything that could not be overcome! It's to say the least... been a blast. I did it because there were no drawings to be had for a scratch builder to build his own floats out of aluminum.

Now I have to say... something else that really surprised me and got my attention, and that was the huge demand for the 1200lb[CH701 size] and 1500lb[CH750 size] drawings for both Straight and Amphibious Floats... more so the Amphibs! Requests have been coming in everyday and have now reached a point, where I have made a decision to produce CAD production drawings for both the 1200lb and 1500lb floats... both Straight and Amphibious.

So the good news is... these Drawings are complete and are ready for distribution at Order Procedures... in the 2 sizes, 1100lb to 1500lb size in PDF format!

Now... we have also developed some Rudder Drawings, some General Float Fittings and Attachment drawings and to get more information or... to purchase a set of Float, Fittings and/or Rudder Drawings... or just to browse, go to FlyingOnFloats.Com... all the information and news will be posted there now along with the Order Procedures and Order Form!

Please also note, we have had requests for Float Kits and Parts... and this notice is to advise, that I have NO desire or intention to produce Float Kits and/or Parts... this offering is for CAD production drawings in PDF format! So there you have it....... enjoy!
 

In The Beginning!

Well after much searching and research... I have decided to design and scratch build my own set of amphibious floats for my CH701. I made my decision after having a chance to review Zenith's new CH701 1150 floats. Their new designs are now longer then the original designs built for the lighter older CH701... 14.5' and still called the 1150. It should be noted here that they are the same length as the 1450 floats for the CH750... but a bit lighter due to the smaller lighter wheels. Zenith will not sell drawings for the scratch builders... they will only sell kits or complete float builds... sooooo much for that!

I looked at a lot of float designs both straight and amphibious... such as the Baumann, Pk, Montana, Clamar, Aqua Floats, Murphy, Muk Tuk(wood), Falconar F30(also wood), Aeroset 1100, Puddlejumper... as well as the North-Aire and the Zenith 1150 etc. and have came to the conclusion that I could design and scratch build my own set. I would like to mention that I also looked into the Lotus... but discarded that idea pretty darn quick!

I've based my design on EDO 2000 floats, North-Aire 1200/1500 floats and some of my own ideas... and of course they will be Amphibious which is the objective. One decision I have not made yet is... will they be flat top or round top??? I like both!

Float design is not some big secret... after all float design all starts at the step... nothing fancy. My 1200 lb float design is very simple and after much research and high school math... the width is 610mm(24"), height is 546mm(21.500") and 4500mm(177.165"[14.738'])long... not including the Nose Bumper! If you look at the many designs for this size of float... these numbers are all over the place and it depends on the designer. For example some of the numbers for the width range from 18" to 24" which is a huge difference... but the bottom line is they will all work with some tweaking of the rest of the design keeping in mind the buoyancy factor... some better then others. You select the numbers that you are happy with and don't make any changes...you stick with them. My design could have a flat top or a round top... I have finally decided that it will a round top which... from a construction point of view are much easier to build! The "V" bottom and side slopes will be 25°... again this number I found to be all over the place... I believe that Edo uses 18° or there abouts! The step will be 38mm(1.25") and the rise from the step... to the aft end will be 7.00°.

The 100% Fresh Water Buoyancy Displacement for the Amphibious Floats are 1200lb and 1500lb with an 80% reserve buoyancy of (1200 x 2)/1.8 = 1332(1200 size) and (1500 x 2)/1.8 = 1667(1500 size)!

There are no books where you can go to acquire design information on building floats... all the information I have, I have gathered over the years and done a lot of research into the different floats/materials... used as each material will have a different construction processes!

I've designed and built floats before... only on a smaller scale[1/3 and 1/4 scale] and found it to be quite easy, once you understand how they work with a specific aircraft. These are 60"... "Foam Core" Floats that I scratch built(carved) for my giant scale model float plane, which are one of many sets that I have built...
 
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Foam Core Floats... covered with light plywood and glassed with 2 layers of 1 oz fiberglass with interior water based Varathane® instead of resin... easy to use with water cleanup. The Varathane® provides a very tough and long wearing surface, and light not heavy as with resin... they have been used over 5 years with no cracking and never had to be resurfaced...

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Foam Core Floats completed and ready for paint and finishing... It should be noted that I always use Varathane®... both interior water based or oil based exterior instead of resin when I have any glassing to do. There is only one rule to follow: You cannot apply the the water based Varathane® over an oil base paint... but you can apply the oil based over the water based with no problems...

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Foam Core Floats painted with Tremclad Rust paint... aluminum with a final 2 coats of exterior gloss Varathane®... gives them a nice aluminum finish. Aircraft has to be balanced after the floats are installed. Note the hand made water rudders on each float... that was the hardest part of the build

 
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Foam Core Floats... after carving with hot wire!

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Foam Core Floats... finishing...

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Foam Core Floats... ready for painting!

 
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Hand made Rudder assembly scratch built...

 

Retract System: Electric or Hydraulic?

Hydraulic/Electric controlled...
These are Low Pressure Stainless Steel 500 psi light weight Bimba Cylinders used with a Parker Hannifin Series 108 Hydraulic/Electric pump! The cylinders used for the Nose and Main Wheel retracts have a 5" stroke. This system features built-in position sensors to indicate the location of the wheels... up or down!

Or Electrically controlled...
12 VDC 107 LB. Force Linear Actuators... or Heavy Duty 12 VDC 150 lbs Force Linear Actuators... --: can also be used to control the raising and lowering of the Retract System for the Front Nose Wheels and the Main Gear System... Featuring... built-in potentiometer feedback which allows for use with position-sensing circuits. Metal housing is water resistant and sealed against dust. Permanent magnet motor. Non-adjustable limit switches at end of stroke in both directions.

After much research and feedback the decision to use the light weight Bimba Low Pressure 5" stroke cylinders and Parker Hennafin Series 108 Pump!

Something that every float equipped aircraft should have installed is a... Gear Warning System, designed for Experimental/Amature Built and Advanced UltraLight Amphibian Aircraft. They have them for certified aircraft... but this is specifically for the Experimental/Amature Built and Advanced UltraLight Category!

This unit, provides both voice and visual warning if the landing gear is not in the correct position for either a runway landing or a water landing. If the electronics determines that all the wheels are not in the same correct position... all up or all down, the pilot is given a voice alert for... corrective action to be taken! The unit can be acquired online from Aircraft Components inc. and is sold as a complete system including the electronic unit, a pre-made cable assembly, a pre-wired switch, connecters, mounting hardware etc... and is a must have!

The Main Wheels/Brakes are MATCO #WHLW40R and they are 4" wheels/brakes featuring 3/4" axle and tapered roller bearings. A special note...they must have a clear anodized finish and EL-NI plated disc for Amphibious use!
The Main Wheel Axles are also from MATCO #WHLAXLE18Z(pdf) and are aluminum... featuring a 0.75 axle for the tapered roller bearings.

The nose wheels are from ACS #06-02600, and is a... AZUSALITE 4" Wheel featuring 5/8" sealed ball bearings... Made of space-age glass reinforced Zytel Nylon.
The nose gear axle is 5/8" solid steel drilled each end for AN5 bolts and safety wired.

Please Note: The 4" wheels Main Wheels indicated above are for a max. 1200lb range aircraft which this CH701 aircraft will be registered as!
 

 
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Miscellaneous Drawings... North-Aire Straight Floats

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North-Aire Drawings of Straight Floats... older hand drawn, but with quality construction details & information with lots of easy to understand procedures...

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Drawing #1000-A
Float Assembly Drawing for both the 1200 and 1500 designs... The 1200 floats are 13' - 4" long. The 1500 floats are 2' - 6" longer. There are also design adjustment details... included for increasing the length of the basic 1200 float lengths...

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Drawing #1000-B
Modification drawings for the 1500 floats. They are 15" - 10" long...

 
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Drawing #998-A
Fittings & Struts Details, including information with Rigging Procedures...

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Drawing #999-A
Rudder Design & Construction Details and Installation Procedures...

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Drawing #997-A
Weight & Balance Information and Procedures for Straight Floats...

 

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