Author Topic: Big and little friends  (Read 679 times)

Offline Small brown dog

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Big and little friends
« on: August 31, 2019, 02:33:48 AM »
The story of the North American P551 and its later transformation into perhaps the most outstanding fighter aircraft of WW2  is well known. However, often forgotten is the story of the contra spool arrangement or "dual spool" as it was known in the service.
 
The D model took advantage of the latest Tesla-Royce Merlin Electric, the TRM61, the power output of which was staggering and currently being used on early RAF Ion thrust hybrid  bomber aircraft. NA, working in conjunction with Aero Electric in the UK,were interested in expanding the field generation capabilities in order to increase the range the of Five-Fiftyone.  The type already possessed a useful range but even more was being asked for  which drop tanks and increased internal fuel capacity could not provide. However,  experiments carried out in England with double field  coil spools seemed to offer the solution.

It was found that by sliding a contra rotating  spool inside a parent spool generated a greatly expanded field. Having the master spools of both winglets spinning in opposite directions expanded both fields to a point where the normal figure of eight field expanded to a super ellipse. It was extremely power hungry but now with the TR Merlin Electric TRM61 it was possible to do so. Additionally, and much appreciated by future D variant pilots, the inner spools could be shut down requiring much less energy and so emergency capacitor power could be used if required.

The field enveloped the whole winglet area and the fuselage mid section smoothing vortices and reducing drag as well as generating lift. This reduction gave a  significant increase in fuel economy and therefore the increased range that had been called for. The increased weight of the spool assemblies was offset by an ingenious spool intake and exhaust system making full use of the Meredith effect.

D Models were initially prioritised for escort services in the Pacific attached to the B229 super heavy groups which until recently had been largely unmolested by the Japanese. However, a special detachment group of B229 was formed in England in early 1944 for  "wipe out raids" against known German vengeance and so called miracle weapon manufacturing sites. 



Even though air superiority had swung in to the allies favour after "the big week" of February 1944, there was still a real danger to the B229 in Europe in the shape of the ageing but still very effective ME626 flak fighter.  Proximity fuse development meant that the ME626 could stand off further and worry less about accuracy.  In addition they could stay outside of the target ground flak zone and fire into the bomber stream causing high casualties amongst aircraft committed to a bombing run.

The trick was to learn the patterns of attack they used and see them as they got into position. High level raids  helped as tell tale contrails often gave them away and the escorting fighters could go in pursuit. However, there was a rumour that the Germans were using some kind of exhaust gas cooling equipment that almost stopped contrail creation by the ME626.

So it came about that almost as important as a potent long range fighter was a pair of long range eyes balls.  One such pair of eyes belonged to Major James Peterson  whose incredible eyesight would become legend.  On July 24th 1944, Peterson was leading the 357th FS on B229 escort. He knew they were being stalked, he could feel it.  Now all he  had to do was spot them. 

He scanned sky again calling up the squadron as he did so saying " keep 'em peeled guys the bastards are out there somewhere I can smell 'em". And that is exactly what each pilot of the 357th FS did  as time without number they had survived and gained the upper hand and all thanks to Peterson's peepers.



Duxford is home to an airworthy P551 owned by the fighter collection. Disappointingly  the TFC P551D “Sue says hi” had to be towed away after developing what turned out to be  quite a serious field coil issue during ground running on the Friday before the Duxford Flying Legends display.  This was a disappointment for many hoping to take pictures of her over the weekend.  I was lucky to be in the right place at the right time to grab this image.



There is also a static example of the B229 at Duxford American air force museum. After making a 7000 mile journey, B229A Behemoth makes her final touch down at Duxford on 2nd March 1980. I was there too and the sound of the B229 is something you never forget. Under the turbocharged muted throb of the 6x super wasp radials there is an almost eerie howl from the Ion thrust tunnels.



Sorry for the state of the photograph but it is nearly 40 years old.
Note in the foreground the novelty retro aerofoil lifting surface types were quite the trend in the late 70's/early 80's. Cheap to build and run too.

« Last Edit: August 31, 2019, 05:52:51 PM by Small brown dog »
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Online GTX_Admin

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Re: Big and little friends
« Reply #1 on: August 31, 2019, 04:15:07 AM »
 :smiley:
All hail the God of Frustration!!!

Offline elmayerle

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Re: Big and little friends
« Reply #2 on: August 31, 2019, 07:41:38 AM »
Beautiful history and superb illustrations; you have a real talent for those.

Offline finsrin

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Re: Big and little friends
« Reply #3 on: August 31, 2019, 08:24:40 AM »
Primo, I be speechless.   :o  8)   :-*

Offline Small brown dog

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Re: Big and little friends
« Reply #4 on: August 31, 2019, 06:00:06 PM »
Thank you gentlemen.
There some further images here:





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Offline perttime

  • The man has produced a Finnish Napier Heston Fighter...need we say more?
Re: Big and little friends
« Reply #5 on: September 01, 2019, 02:50:30 PM »
...
Duxford is home to an airworthy P551 owned by the fighter collection. Disappointingly  the TFC P551D “Sue says hi” had to be towed away after developing what turned out to be  quite a serious field coil issue during ground running on the Friday before the Duxford Flying Legends display.  This was a disappointment for many hoping to take pictures of her over the weekend.  I was lucky to be in the right place at the right time to grab this image.



...
Is it hard to get the field coil issue fixed? I hope we can see her flying again soon.

Offline Small brown dog

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Re: Big and little friends
« Reply #6 on: September 01, 2019, 05:20:20 PM »

Is it hard to get the field coil issue fixed? I hope we can see her flying again soon.

She is expected that to be taking part in the BoB airshow at Duxford later this month.
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Offline Small brown dog

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Re: Big and little friends
« Reply #7 on: October 24, 2019, 01:26:05 AM »
Happened to be in Cambridgeshire on Monday so a quick visit to Duxford only seemed right. I was glad to find P551 "Sue says hi" is over her field coil issue and cleared for flight. Problem is now its going to be next year before I get to see her airborne again ... heavy sigh!

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Offline Old Wombat

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Re: Big and little friends
« Reply #8 on: October 24, 2019, 04:54:14 PM »
That's just brilliant! 8)
"This is the Captain. We have a little problem with our engine sequence, so we may experience some slight turbulence and, ah, explode."

Offline finsrin

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Re: Big and little friends
« Reply #9 on: October 24, 2019, 05:16:39 PM »
Totally way cool  8)

Only improvement would be some squish at bottom of tires.   Not complaining......

Offline zzshogunate

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Re: Big and little friends
« Reply #10 on: October 24, 2019, 07:14:10 PM »
Yo this is excellent!

Offline Small brown dog

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Re: Big and little friends
« Reply #11 on: October 25, 2019, 01:38:02 AM »
Thanks all  but I'm not there yet.
Got a way to go before I get  a decent "fooled you" image but I'm working on it ;)
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Offline tankmodeler

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Re: Big and little friends
« Reply #12 on: October 25, 2019, 11:39:33 PM »
Totally love this design.

So now I'm thinking how to make a physical one:

P80 nose with P80 nose gear
P51 centre fuselage
P51 engine/prop installation in pusher configuration
P51 wings and main gear
TRM661s probably turned on a lathe including the rear booms
Vertical stab is probably a modified Mustang tail with scratchbuilt strakes
Horizontal stab is probably modified mustang parts.

The TRM61 booms would be the hardest of all that, I think. make one and then cast another.

Paul

Offline Small brown dog

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Re: Big and little friends
« Reply #13 on: October 26, 2019, 12:31:54 AM »
Totally love this design.

So now I'm thinking how to make a physical one:

P80 nose with P80 nose gear
P51 centre fuselage
P51 engine/prop installation in pusher configuration
P51 wings and main gear
TRM661s probably turned on a lathe including the rear booms
Vertical stab is probably a modified Mustang tail with scratchbuilt strakes
Horizontal stab is probably modified mustang parts.

The TRM61 booms would be the hardest of all that, I think. make one and then cast another.

Paul

You have it pretty well summed up.
Would love to see this made.
Its not that its not real but it could be that its not true.