'Increasing the Charge' - how piston engine technology provided the power to fly

[J.A.W.]

Thanks J & T, for that input..

Here is a performance graph showing speed @ height - for the new twin-engined RAF fighters,
Hornet & Meteor, - along with the fast Merlin & Griffon single engine powered RAF fighters.

http://www.wwiiaircraftperformance.org/Hornet/Hornet_I_Level_AFDS.jpg


The Mosquitos equipped with 2-stage supercharged Merlins featured a longer nacelle yet -with the engine
air scoop located below the spinner, similar to the Mustang.

The Hornet F 1 - when tested with the initial typical De Havilland-shaped fin/rudder did exhibit directional
stability issues ( no minor thing on a twin ) & had a fin fillet added - similar to the Tempest..

(Most late production, high powered piston engine fighters required & received more tail aero surface area).

 

[J.A.W.]

& the 'shrouded' ( flame dampened for night flying) Mosquito exhaust arrangement cost ~15mph..

http://www.wwiiaircraftperformance.org/mosquito/dk290-b-.pdf

 

[Hot Breath]

As the thread devoted to large aero-engines is locked, I'll post my question here. What was the exhaust arrangement intended to be on the Rolls Royce Exe? Was it one set of exhausts per side, with two cylinder banks collected together or was it like the Vulture which had two sets of exhaust per side?

 

[J.A.W.]

See this 'Flight' article , H-B..
.. which conveniently has a picture of the flying Exe - to contrast with the Vulture arrangement shown stat below..

http://www.flightglobal.com/pdfarchive/view/1948/1948%20-%200146.html

 

[J.A.W.]

This chart shows the performance available to the early series Merlin Mustang ..
..running on various supercharger ratios & boost settings ( & at low AUW)..

http://www.wwiiaircraftperformance.org/mustang/P-51_B_High_Speed_Performance.jpg

 

[J.A.W.]

The Brits & the USN weren't sold on turbos.. - not for fighters at least- & the R-R Merlin in the Mustang showed why..

However, the USAAF did give turbo fighters a good go, even if they were expensive/complicated/bulky in usual US-style..

Here, the G.E. sales pitch for the big ol' Thunderblot..

http://rwebs.net/avhistory/opsman/geturbo/geturbo.htm

 

[J.A.W.]

& NAA/Packard felt it worthwhile to see the ADI R-2800's commendable 70" of boost..
.. & go to 90''/ADI for the P-51H/Merlin V-1650/9..

Here is the power chart.. http://www.wwiiaircraftperformance.org/mustang/p-51h-powercurve.jpg

 

[J.A.W.]

& here..
http://www.wwiiaircraftperformance.org/mustang/Comparative_Fighter_Performance.jpg
A USAAF graph equivalent to the British comparison(post #241)..
..between late piston-powered fighter performance & the new jet job..

& with the caveat however, that judging by the date.. ..it is an estimation..
..Also, the Mustang is at 70" boost, same as the P-47, & 20" less than the max of 90" Hg/MAP - it was cleared to run..

 

[tartle]

There is an interesting 'manual' on turbosuperchargers here on Randy Wilson's website along with much other interesting material. [someone has pointed out this is the same link as J.A.W.'s in #246 above ... great minds or a lazy mind?]

 

[J.A.W.]

& the 'bomber' Junkers Jumo 213 V12 - as applied to the FW 190D.. ..engine finally runs ~5min in..

http://www.youtube.com/watch?v=4Y5LBUVS1T8

 

[J.A.W.]

This USAAF appraisal of the Lancaster shows enthusiasm for the "many automatic features" applied to the engines..
..including cooling, mixture & etc settings , - just as they did for the same measures applied to the Merlin in the Mustang..

http://www.wwiiaircraftperformance.org/Lancaster/Lancaster_Eng-47-1658-F.pdf

 

[J.A.W.]

This article by Kevin Cameron considers the thermal load/TBO aspects of piston engine power outputs..

http://www.cycleworld.com/2014/05/23/engine-tech-how-much-power-for-how-long-by-kevin-cameron/

 

[J.A.W.]

From the long 'much maligned British automotive engineering' dept..

Bernard Hooper was a Norton engineer back in the 70's - with some innovative ideas, & has persevered,
viz.. http://users.breathe.com/prhooper/uav.htm

Back in the day, his bosses felt going down the Cosworth F1 path was the better option, but they were wrong..
As can be seen in this well written technical appraisal of the engine by Kevin Cameron..

http://classicbike.biz/Norton/Mags/1970s/Cosworth-Norton.pdf

 

[tartle]

Fascinating... I guess if we only have two tools-hubris and a hammer - we'll see each problem as needing a nail!

 

[J.A.W.]

107 years ago, Glenn Curtiss was the "Fastest Man on Earth" at 136.36mph - with a V8 aero-engine of his own manufacture..

This speed was achieved across a measured mile at sea level, in fact - along a Florida beach, & riding his motorcycle..

http://www.odd-bike.com/2012/11/curtiss-v8-worlds-fastest-motorcycle.html

After his first flight Curtiss was quoted.. "Not bad sport, but there's no place to go"..

So he designed sea planes, & his aircraft were the first flown from warships & to cross the Atlantic..

 

[tartle]

Curtiss was designing his own motor bike engines and then in 1907 Alexander Graham Bell asked him to design an engine for a heavier than air flying machine... the rest ids history.. the book I have just finished and nearly edited features Curtiss.His later (WW1) engines were not as robust but that is a story for elsewhere.
The picture below shows his Reims racer at Reims 22-29 August 1909 with his new light-weighted V8 water cooled engine.

 

[mz]

SDASM archive on flickr has lots of photos of similar flying machines and of Curtiss himself. It's a bit hard to know when they are photos of a later replica though.

 

[tartle]

I can vouch for that one as it was taken on a visit by Maurice Egerton to Reims and I have catalogued many others on the other machines too! Maurice was a keen photographer.

 

[J.A.W.]

Curtiss was designing his own motor bike engines and then in 1907 Alexander Graham Bell asked him to design an engine for a heavier than air flying machine... the rest ids history.. the book I have just finished and nearly edited features Curtiss.His later (WW1) engines were not as robust but that is a story for elsewhere.
The picture below shows his Reims racer at Reims 22-29 August 1909 with his new light-weighted V8 water cooled engine.

The Curtiss 'Golden Flyer' which won G.C. the Bennett Trophy at Rheims..

& his 'Gold Bug' got him a law suit from the Wright Bros, when he sold it - over his development of ailerons..

The link in post #255 has a brochure featuring his line-up of aero-engines, listing weights/powers/cooling/configurations..

 

[tartle]

The Golden Flyer is a different aeroplane to the one that went to Reims... Curtiss built a new aeroplane incorporating lessons and to take account of the racing that he would be doing.
We should start a new thread for this.

 

[J.A.W.]

Well, T, if you've got a proper book on the subject, I'll leave it to you..

& here - a vid which demonstrates the sophistications of the technicalities pertaining to operating a Corsair.
( & shows why the Americans were so impressed with the automation of controls - as developed over the Atlantic)..

http://www.youtube.com/watch?v=R4aPk4fledU

 

[J.A.W.]

Here, a compact currently commercially available piston engine - that offers upwards of 200hp from 95lbs, un-boosted..

http://www.aaenperformance.com/V4_racing_engine.asp

 

[J.A.W.]

This vid shows the pre-flight engine protocols for the Bf 109G, & provides a Euro-contrast with the fiddle-faddlin' F-4U..

http://www.youtube.com/watch?v=7Sz5t-m9IOE

 

[J.A.W.]

Manufacturing Merlins, the Packard way..

http://www.youtube.com/watch?v=hRVWyZf5MQk

 

[tartle]

JAW... very interesting. There are some IWM films of Merlin production at Hillington and Trafford Park but I've not found them on the web yet.

 

[J.A.W.]

Glad you found it so, T..

Could this be one that you are thinking of?

http://www.youtube.com/watch?v=uzYxBbitP_s

 

[tartle]

Ta.. and this... Hillington did most manufacturing in-house as the 'hi-tech' production infrastructure in Glasgow did not really exist... hence RR had to do it all from necessity not choice.
https://www.youtube.com/watch?v=aX7NlO9nWi0

 

[J.A.W.]

Good stuff, T..
& the same sorry skill base issues applied for Napier/EE in Liverpool..

..Don't suppose there is a similar film about Sabre production though, too hush-hush at the time - or something..

 

[tartle]

there is a similar story about the shadow factories for Bristol engines tooo which were supposed to be better as Fedden's team spent more time on DfP ... and car firms made up the labour/management pool... first signs of demise of car industry?
Oh for a Napier film! best available stuff seems to be pix at IMech EAlso hard to find engine info at Kew ... my last frustrating half day -their cameras were playing up and I did not find much beyond continual asking for more cash to spend on factory and test facilities and not much on engine itself!

 

[J.A.W.]

This 'Aeroplane' article featuring the R-R Griffon shows useful schematics of supercharger drives,
& an output figure comparison with the R-R Eagle V12 of WW1 - as a means of showing piston engine power progress.

http://www.spitfireperformance.com/RR-Griffon.pdf

 

[J.A.W.]

Work/research still continues on the venerable piston engine..
This paper considers tribological effects on piston to cylinder liner surface patterning.

http://www.federalmogul.com/en-US/Media/Documents/HighqualitySAEpaper200909PFL1163manuscript2.pdf

 

[Kevin Renner]

Here, a compact currently commercially available piston engine - that offers upwards of 200hp from 95lbs, un-boosted..

http://www.aaenperformance.com/V4_racing_engine.asp

Less than 5 miles from the house actually

 

[J.A.W.]

Hey, K.R., that's great, can you get down there with an HD Video camera..
& put us up some high-production value 'footage' of the machine on dyno test?

 

[J.A.W.]

USAAF statistical chart showing WW2 piston engine overhaul hours by type..

http://www.usaaf.net/digest/t115.htm

 

[tartle]

JAW,
A useful find!
Must do some bmep calculationss to see what accounts for differences... configuration, performance per unit of ? or mechanical design...tbc.

 

[J.A.W.]

Yes it is a bit interesting T, but whether the time difference spent on fettling the two V12s was due to the..
..typically Brit nuts 'n' bolts construction architecture of the Merlin, & unfamiliarity with such - or due to being run harder..
..may also be a point of inquiry.. ..certainly the number of parts listed per the Merlin is rather larger than the Allison..

 

[alertken]

1820 consistently lower than 1830 - the competing engines for C-47, yet post-War civil preference was for Pratt.

Good luck in analysis, but operational, rather than design technical issues may be significant: e.g: this is CONUS Depots: battle damage/ misuse may have been handled more in Theate Depots

 

[JFC Fuller]

Tartle,

This may interest you. I found yesterday a mid-1944 reference to a "three stage" Merlin to possibly be available in 1946 in relation to the Spiteful. I have nothing more than that I am afraid, no type numbers, only this one reference. Perhaps you are aware of some work undertaken in this direction?

 

[tartle]

Fascinating,
It is possible a designer schemed out such a concept but I haven't so far found any evidence.
Is there a possibility that this is similar to a reference I found to a 3-stage supercharger for the Griffon that on chasing it through the paper trail turned out to be a 3-speed supercharger? Not knowing the provenance of what you found I can only speculate...
what are your thoughts?

 

[JFC Fuller]

I actually mused exactly the same thing, that perhaps it was a confused reference to a Merlin with the sort of two-stage/three-speed supercharger used on the 100 series Griffon. The original Merlin engine schemed for the Merlin Spiteful variant was the RM.16SM (as used in the Spitfire PR.Mk.X). Of equal interest, to me at least, was an assertion that a Spiteful with the Merlin would have approximately 8-9% more range than the Griffon powered version.

On a lighter note I found myself having considerable sympathy for the people at RR and Supermarine in particular. After all the work undertaken on developing the Spiteful and the high-altitude Griffon to power it the Air Staff decided in mid-late 1945 that their only interest in the type was as a low altitude attack aircraft, so the whole programme was held up as Supermarine worked to install the ability to carry a 1,000lb bomb under each wing.

I didn't think this picture would work, but it does just about, its from the Spiteful files I was looking at, Griffon 65, versus Merlin 66 versus RM.16SM: