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Short Crusader 1927

PostPosted: Sat Aug 08, 2020 3:09 pm
by longshot
Schneider Cup contender....fits the Seawings page, too!!
Image

Re: Short Crusader 1927

PostPosted: Sat Aug 08, 2020 6:23 pm
by dogsbody
Nice! Both the photo and the sizing.



Chris

Re: Short Crusader 1927

PostPosted: Sun Aug 09, 2020 5:50 pm
by schneiderman
Wind tunnel tests showed that the fuselage/engine produced as much drag as the entire Supermarine S5.........and then cooling issues led to them removing the cylinder 'helmets' to make it worse. The supercharger intake was in the highly turbulent air behind the cylinders and the engine could not be made to run smoothly.

On the plus side the large and detailed wind tunnel model was used in the development and evaluation of the Townend ring, so some good came of it all.

Re: Short Crusader 1927

PostPosted: Mon Aug 10, 2020 1:53 pm
by longshot
It's heresy to mention it on Seawings but what percentage of the total drag did the floats and struts account for at maximum speed with these Schneider Trophy racers?

Re: Short Crusader 1927

PostPosted: Mon Aug 10, 2020 5:28 pm
by schneiderman
Not as much as you may imagine.
For the S5 in 1927 it was 24%, from wind tunnel evaluation of the 1/6th scale model. I can't find the S6 numbers at the moment but I may have included it in my S6B Haynes guide.

Re: Short Crusader 1927

PostPosted: Wed Aug 12, 2020 2:21 pm
by longshot
Thanks, Schneiderman. Did any of the Schneider competitors experiment with floats and struts which could be jettisoned to measure the increase top speed (followed by a landing on skids, perhaps) ? It just seems an obvious thing to try

Re: Short Crusader 1927

PostPosted: Thu Aug 13, 2020 9:05 pm
by schneiderman
There were a couple of flying boat projects with retractable planing bottoms but nothing that involved jettisoning parts. However such ideas would have fallen within the rules, which were pretty broad. Despite their exotic appearance most of the racers built were actually pretty conventional, it was the engines that were the 'high tech' element. Interest was waning and costs getting unacceptably high when the contest was finally concluded but in a parallel universe maybe it would have continued and really on-the-edge designs brought forward.

Re: Short Crusader 1927

PostPosted: Tue Sep 01, 2020 3:11 pm
by longshot
Veering a bit from the Schneider racers it occurred to me that there might be some information published on the reduction in maximum speed for various landplane types modified with floats. The first I found was for the Grumman F3F Wildcat...the Putnam book records some 60mph reduction from the wheeled F3Fs 328mph maximum speed (perhaps unsurprisingly)
Image

(No doubt the Edo float company had standard claimed figures for their products. A C-47 website suggests the Edo floats on the C-47 reduced its cruise speed by 30 mph.)

Re: Short Crusader 1927

PostPosted: Sun Sep 06, 2020 9:36 pm
by schneiderman
Its hard to find reliable like-for-like data but the 1925 Curtiss R3C-1 landplane did 245mph average in the Pulitzer Trophy and was then put on floats, as the R3C-2, for the Schneider Trophy immediately after where it averaged 232mph. Ultimate 'straight line' speeds cannot be compared as that recorded for the R3C-1 (about 285mph) was after a steep dive while the speed record set by the R3C-2 (245mph) was under strict FAI rules.
The only difference between the aircraft was the replacement of the wheels by floats, but the race courses were of different configuration hence not directly comparable. Fixed undercarriage created a lot of drag.

Re: Short Crusader 1927

PostPosted: Mon Sep 07, 2020 8:29 am
by schneiderman
Again, maybe not directly comparable given all the engine mods, different props, better fuels and so on but the Spitfire VB did 370mph while the V on floats did 324mph.