Sopwith Baby Project

Joe Perkel · 30 August 2008, 08:01 AM

Pete,

Thank you for that well thought out and informative response.

I agree, it's a rough guess at best which would, as you note require field confirmation but, also agree that it's a place to start.

Creating this calculator is beyond my capability but, as I said, I'm willing to post a dedicated page of something useful for all to access.

Interesting to me to see how these antique technologies reached a peak, then gave way to newer stuff before they could be improved further. Examples are the Steam Engine as well as these Rotary Aircraft Engines.

Thanks Pete!

lake flyer · 30 August 2008, 12:35 PM

Joe ,

Thanks for your reply re: Tabloid wing .

Have you given any thought to filling the floats with low density foam , no chance of imbalance from water leakage .

Joe Perkel · 30 August 2008, 01:08 PM

Quote:

Originally Posted by lake flyer

Joe ,

Thanks for your reply re: Tabloid wing .

Have you given any thought to filling the floats with low density foam , no chance of imbalance from water leakage .

Lake Flyer,

Although a CFI, I have zero float time or experience with floats. Muk-Tuk, in your neck of the woods, is consulting on my float re-design, and did not mention foam as yet but I will ask. I don't know enough about the issues to make an educated response yet about the foam, although it certainly appears to be something to consider.

What is the density of such a foam? With the density, I could quickly calculate the weight penalty.

Also, where free surface effect would be eliminated and that is a good thing, I would have a question regarding any chances of long term absorbtion. Or any other reasons to may have to dig it all out at some point.

lake flyer · 30 August 2008, 07:12 PM

I do not know the technical details ( water absorbtion etc. ) , densities are in the order of 1.75 - 2.0 lbs / cu. ft.

Here is one vendor -

Handi Foam SR Two-Component Poured-In-Place Foam

Joe Perkel · 30 August 2008, 08:36 PM

Quote:

Originally Posted by lake flyer

I do not know the technical details ( water absorbtion etc. ) , densities are in the order of 1.75 - 2.0 lbs / cu. ft.

Here is one vendor -

Handi Foam SR Two-Component Poured-In-Place Foam

Ok, so with each float @ 19.5 cu ft, it's not sustainable at 39 lbs each. The idea of being able to eliminate free surfaces and the potential dangers therein, is a valid one but, too costly in the 80 lbs extra weight.

I think preflight in this would be a bit extra special! I'm just going to have to be careful. The aft hand-hole, a bright light, inspection mirror, and a hand bilge pump, will have to be part of the routine then.

Thanks for the link!

drrivah · 31 August 2008, 04:54 AM

Hi Joe:
What is the distance between center of thrust line and surface (ground) for the Baby (prop clearance)? Does this differ, ground surface vs water?

Recommended (minimum) clearance between prop tip and ground was
11" for a/c in level flying attitude according to old design texts, but may be more (13"?) for water: can you confirm numbers for Baby?

What are prop clearance vs water surface considerations for seaplanes?

Not sure how such numbers are determined, but the 11" was apparently required by federal regulation by Dept. Commerce in 1920s. No idea why 11".

Thanks.

-pete

j ferguson · 31 August 2008, 05:00 AM

Might be fun to have a plimsoll line on the floats just as a quick check. I suspect that you are never going to leave it overnight in the water.

John

Joe Perkel · 31 August 2008, 05:18 AM

Quote:

Originally Posted by drrivah

Hi Joe:
What is the distance between center of thrust line and surface (ground) for the Baby (prop clearance)? Does this differ, ground surface vs water?

Recommended (minimum) clearance between prop tip and ground was
11" for a/c in level flying attitude according to old design texts, but may be more (13"?) for water: can you confirm numbers for Baby?

What are prop clearance vs water surface considerations for seaplanes?

Not sure how such numbers are determined, but the 11" was apparently required by federal regulation by Dept. Commerce in 1920s. No idea why 11".

Thanks.

-pete

Pete,

Hopefully, I have a single drawing somewhere with this information. I can answer these when I have the CAD model done but, I am well behind on this. Off hand, I think the prop disk is 102", spectacularly massive! The tip clearance from the floats is minuscule and the floats somewhere about 18" high.

Quote:

What are prop clearance vs water surface considerations for seaplanes?

Will have to look this up as well, I'm sure it's not arbitrary.

What's on your mind?

Joe Perkel · 31 August 2008, 05:24 AM

Quote:

Originally Posted by j ferguson

Might be fun to have a plimsoll line on the floats just as a quick check. I suspect that you are never going to leave it overnight in the water.

John

John,

I think you've flown floats in Florida. Al. floats I'm sure condense plenty but, shouldn't I get some insulation effect from wood?

You're correct, no overnight mooring! Can't get caught out and let this be subject to any afternoon summer boomers either, this is going to be a fair weather bird!

P.S. You're nice and safe up there in Maine for the season. I'm feeling like a bowling pin down here between Gustav and Hanna!

j ferguson · 31 August 2008, 05:40 AM

Quote:

Originally Posted by Joe Perkel

John,

I think you've flown floats in Florida. Al. floats I'm sure condense plenty but, shouldn't I get some insulation effect from wood?

You're correct, no overnight mooring! Can't get caught out and let this be subject to any afternoon summer boomers either, this is going to be a fair weather bird!

P.S. You're nice and safe up there in Maine for the season. I'm feeling like a bowling pin down here between Gustav and Hanna!

Hi Joe,
Not Florida. Wisconsin and a Goose which lived on land and only got wet briefly. It was a total rebuild and didn't leak much at all.

I would think you would want to be able to inspect every inch of the interior of your floats since they are critical and subject to structural shocks. I also suspect you're not going to have much trouble with condensation. Arcadian is fiberglass and we only get condensation in the black iron tanks.

Something else which is probably obvious is to have a really easy effective way of beaching the plane. If it isn't a real breeze and can be done by two people, maybe even just by yourself, you may be tempted to leave the plane in the water when you should be pulling it out.

Best regards, John