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        Discussion New Amphibian Design for R/C and Full Scale Homebuilt

#1 canardjeff Oct 11, 2012 11:21 AM

New Amphibian Design for R/C and Full Scale Homebuilt
 
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Hello All ,

Here are a few pics of a proof of concept model I am building to test out in R/C form a new design I have just completed for a full scale LSA category kitplane ( 100 horsepower, two place). Will probably pull molds off model if successful and market it as well too. Been in this hobby since eight years old( 53 yrs old now) and have transitioned into full scale design and manufacture about 15 years ago ,experimental class kitplanes. Let me know what you think of her and if you feel there is merit in selling a model kit. It is quarter scale at 102 inch span and 72 inch long, will power with 110 to 160 electric. Fuselage side sponsons and engine cowling on top of wing for recessed engine installation on full scale yet to be added. Sponson and cowling designs look sweet. Will fly in primer and pretty it up after initial testing for full scale exercise.

Jeff Kerlo

#2 pmisuinas Oct 11, 2012 02:12 PM

Looks like a high wing Shearwater...

#3 canardjeff Oct 11, 2012 04:27 PM

Forgot about the Shearwater , it kind of fell off the map so to speak. Similarities?, well they do share the V-Tail . In planform which I dont want to show yet they are markedly different. But as that old saying goes " Form follows Function" and as such two items optimized for the same mission tend to end up similar in numerous ways. It is quite different than the original Shearwater , but the new Hydroski version I see has similarities. What do they say, Great Minds Think Alike?

J

#4 canardjeff Oct 11, 2012 04:35 PM

The original Shearwater prototype seems to have had a lot of influence from the Seawind. Looks almost as though the front half of the Seawind fuse might have been grafted onto a new aft fuselage.

#5 rich6170 Oct 11, 2012 08:06 PM

looks more like an ICON with a v tail.....

#6 Teambreen Oct 11, 2012 10:15 PM

Congratulations on a great looking Seaplane. Do you have a projected weight?

#7 canardjeff Oct 12, 2012 08:19 AM

I am going to initiate testing at 16 pounds, scale weight however is 23 pounds. Wing area is roughly 1150 sq.in. Will ballast in increments up to scale weight to simulate solo and dual occupant weights. I see you are from Lake Wales, do you by chance know Scott Smith( pylon flyer) I recently raced over at the Mulberry Field

#8 Renfield Oct 12, 2012 03:01 PM

Quote:

Originally Posted by rich6170 (Post 22977115)
looks more like an icon with a v tail.....

+1.

#9 Petem Oct 13, 2012 12:39 AM

Nice lines!
 
A very attractive design.
All the best for your project.
PeteM

#10 Teambreen Oct 13, 2012 11:21 PM

I am not Familiar with Scott Smith Does he Live in Lake wales? How did it go at the Pylon meet ?
I hope you will keep us posted on your design.
Mike

#11 canardjeff Oct 14, 2012 02:40 AM

Will definitely keep you posted on progress and developments. If all goes well , will be test flying next week in primer. Will wait till after prelim testing to put a proper finish on it and detail cockpit to simulate real version. Will conduct first few flights off runway then go to water after verifying stability. Saw your big Aeronca , Mike, really nice job. Looks like it flys well too. Pylon meet went well . I hadnt raced in a touch over twenty years , went over to visit old friends and got dared to come back on Sunday and put together an airplane from bits offered by the challengers. So I came back sunday with my transmitter and receiver and was loaned an airframe from Gary Freeman jr and an engine from another friend, threw it together for a quick trim flight. Ended up setting fast time for the day and finishing second, went home with two trophies Surprised everyone , but mostly myself. Starting the day I just hoped to give the guys their stuff back in one piece. Had a great time, to say the least

#12 canardjeff Oct 14, 2012 02:44 AM

Scott does live in Lake Wales , he is president of Southeast Miniature Pylon Racing Assoc. and belongs to the Imperial club in Mulberry, really great guy!!

#13 parkcityskier Oct 15, 2012 07:23 AM

I flew a Bonanza V-tail for quite awhile and always liked it but a lot of pilots didn't like the "Dutch Roll" tendancy in turbulence and the V-tail eventually went away. You might be turning away a segment of the pilot population with your V-tail design, although for the limited use of the sport category designs, being flown in only the best of flight conditions, perhaps it won't be an issue.

#14 canardjeff Oct 15, 2012 11:07 AM

Yes , considered that possibility. Living down the false bad rep the Bonanza acquired. Do have an alternate cruciform conventional tail designed as well . Airframe can go either way cruciform tail would be a vertical extension of V-tail saddle. Probably an optional offering . I have built , flown , as well as raced many v-tail models and they all have flown great, in the racing world most would argue , better than conventional. Talked to numerous Bonanza owners, one of which a friend Corkey Fornof, he , as well as others, loved the airplane and said most of the problem is pilot induced. One thing bad was that there was no differential throw in the ruddervators which caused adverse yaw of the tail which would promote tail wagging. This airplane design is actually a Y-tail , elevators only with a wide chord rudder below V-tail. If necessary ruddervators can be incorporated thru a mixer with differential, hopefully not required.

#15 Cougar429 Oct 16, 2012 07:30 AM

It's always great to see something new like this and I commend you on your effort to date. I will be following this one with interest.

I was going to mention some info on the Bonanza, but it looks like you have that well in hand. There definitely is an advantage cutting down the number of flight surfaces poking out into the airstream and from what I remember Beech only returned to the conventional tail to proceed with what was otherwise a rather robust design beyond the negative publicity.

Again, this is from memory, but along with the aforementioned PIO problems Beech had also reduced the structural strength in the tail block during production, (and the fact it was magnesium) leading to the failures. It can be noted the original design did NOT suffer structural failures.

My father and I were interested in the Seawind back in the mid to late 70's and I met the original designers/builders when I stopped in their factory back in '83. The nose definitely does NOT look anything like it at all and I would confirm the shape is more akin to the A5 sans the sponsons. True about form following function.

On that note, I have only one observation regarding the lack of tip or mid-span floats. With just the central hull design one would suspect a rolling tendency in any form of crosswind or rough water ops which would only stop once the wing reached the surface AND had some form of floatation component.

If that occurred with any speed on you would risk severe structural loading and/or damage. In fact, I asked Dave Thurston back in the mid 80's on his thoughts of what I called the "Wooden Shoe" original tip floats and he confirmed the prototype had already dug one tip in and flipped causing fatalities.

You also have to look at the placement of the engine to the buoyancy width. If the plane suffered a roll where the engine weight extended beyond the width of the existing floatation points, (or inertia was getting close to that point) then the roll would continue with no counterforce until I suspect completely inverted.The higher above the natural roll axis the more likely this can happen and the less it would have to move sideways to extend beyond that natural roll counterforce. Any fellow heli pilot could compare this to what we call "Dynamic Rollover".

Only other question I can think of at this time is if this will be dedicated water ops or are any plans for an amphib version?

p.s. As a follow on to the Bonanza tail issue, anyone else remember the history of the Lake amphib "Bat-Wings"? Very similar in process.


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