Wingload - tables for AH planes

[Angus]

I presume both airscrews were 3 bladed, so that would not be the problem. Anyway, the Rotol CS screw enhanced the climb rate drastically, although seemingly at the cost of a little top speed. I wonder what it did to acceleration though.

[Badboy]

Originally posted by Angus
I presume both airscrews were 3 bladed, so that would not be the problem. Anyway, the Rotol CS screw enhanced the climb rate drastically, although seemingly at the cost of a little top speed. I wonder what it did to acceleration though.

Nope, I actually checked, lists of MkI serials indicate that during these trials, K.9793 was fitted with a two blade propeller, and N.3171 had a three blade constant speed propeller. So additional solidity was an important factor that partially accounted for the improved climb rate and acceleration and the slight loss in speed as explained in my previous post.

The increase in acceleration would have been as obvious to the pilot as the improved climb rate, and there is an account written by a WWII pilot who describes the effect of his new constant speed propeller during mock combat by saying that he felt the acceleration was double what it had been previously.

Naturally, that sort of anecdotal evidence only serves to demonstrate that it indeed had an impact on the pilot, perhaps he was exaggerating slightly to make his point, but since climb rate and acceleration are linked, it is certain that an increase in climb rate would have a corresponding effect on acceleration.

Hope that helps.

Badboy

[HoHun]

Hi Angus,

>I wonder what it did to acceleration though.

To add to Badboy's comments, acceleration is linear to climb rate (at the same speed). Going at best climb speed, the Rotol Spitfire would have felt a dramatic improvement of acceleration.

Off course this became less noticable at increased speed, and finally the two-pitch propeller would give a better acceleration near top speed. The two-pitch Spitfire couldn't have been faster else :-)

Regards,

Henning (HoHun)

[Angus]

Just a little question:
Why would the top speed be more for a manual 2 pitch propeller with 3 blades then a CS propeller also with 3 blades? Was the CS propeller not able to go to as course a setting as the manual one?
Were the Germans also using similar technology, or were their prop controls very much different?

[gripen]

Badboy,
Earlier NASA database (CASI) contained much more NACA papers than current (NTRS), but even CASI database did not contain so called "NACA confidental bulletins" which appear to be very interesting part of the NACA papers. Hopefully they will scan this part of NACA papers in the future or at least ad them to database.  AFAIK NACA made something like 40000 papers (reports, memorandums, bulletins etc...). Currently they have scanned something like 10000.

gripen

[dtango]

Great discussion going on here.

Tilt - if the shorter parabolic lines were for flaps fully lowered then they would probably be similar and above the other curves since CLmax typically increases with flap deployment.

gripen - yeah, that's a tough one regarding the NACA ACR's/ Wartime reports.  From what I can tell there isn't much going on in that respect in getting them digitized.  I've found a local source in Houston but it requires knowing which ACR/Wartime report you are looking for since most of the stuff is mainly in storage as bound books and there is no way to have them all hauled out for browsing.  I have enquired the NASA CASI folks regarding a listing of the titles for all the ACR/Wartime reports so that I can start picking a few out but what they gave me in reply was no help whatsoever.

Tango, XO
412th FS Braunco Mustangs

[Angus]

Talking about digitalizing WW2 material, i.e. photos, films, and documents, there is indeed not very much going on.
I am not sure what it is all about. The IWM has a free admission to even the photo and film arcives, but individual documents/films/photos have to be bought/licenced if you want to take those home with you.
The PRO has so much, and yet not all. Very little is digitalized, althoug on both places inquiries can be placed and answered by email, and a rough internet inquiry will lead you towards your research matter.
Maybe lack of funds or something like that. I do not know. However, in the long run, it would be a lot cheaper to digitalize the whole bunch right away. As it is, it´s using exactly the same storage and search technology as in the 40's for that sake.
Oh, IWM=Imperial War Museum, UK, and PRO=Public record Office, UK.
Both great places to visit, mind you!

[Tilt]

Originally posted by dtango
Great discussion going on here.

Tilt - if the shorter parabolic lines were for flaps fully lowered then they would probably be similar and above the other curves since CLmax typically increases with flap deployment.

Tango, XO
412th FS Braunco Mustangs

Of course your right............ then I would assume that some how in these tests they formulated a curve for gear down?

[Angus]

By the way, - although wingloading does not have ALL to say about  i.e. turning quality of an aircraft, it still has MOST to say.
AH aircrafts turn rates almost go paralell to their wingloading, with perhaps some exceptions though.
Oh, and I wish you all a good new year('s)

[Angus]

This is an old thread, but in regard of some aerodynamic questions being asked on the forum, I belive it desreves to be punted.

So, risking the wrath of Pyro, I say:

PUNT

[Crumpp]

Thank you Angus.

This thread is right on target with Max CL and it effects on performance thread I started.

Can anyone explain further?  So far the concensus in that thread has been that Max CL does figure into turning performance.

Question is just how much does it?

Crumpp