Me-109/Bf-109 Questions

[Augsburgeagle]

Augsburg, as for as prop rotation, one of us is confused.
I think you are mistaken, if you believe that there is a difference in the direction of prop rotation of a Me 109 with the original D B type engine, and the Spanish version with the Merlin.
I have read and heard of this a number of times, but think it is a myth.
I have looked at several Hispano 109s with a Merlin, as well as stood beside, sat in ,flown beside, and watched the start up, taxi and flight of the Me 109 in Canada with the original type D B engine. Unless I am blind they all turn the same direction as to prop rotation.
If you were in the cockpit, and the blade was pointing straight up, it would move down to the pilots right, thus turn clockwise as the pilot sees it.
This is the same for a Merlin or a DB, whether the engine is in a Me 109 or a Hispano 109, or Spitfire or Hurricane or P-51 , or P-40. As a matter of fact the same as most planes with a few exceptions like Centaurus, Griffon, Gypsy engined planes.
To be sure, I got out some photos of DB engined 109s and you can see be the prop blade angle what the direction of rotation is. I have looked in several different books, I can quote the titles and pages if you need.
I only know Dave Southwood by reputation, but I doubt if he told you that the props turn opposite directions. If he did perhaps it was after a trip to the pub and from years of driving on the wrong side of the road.

I may be wrong, but I don't think so. Are you interested in a small wager on this?

What do you or anyone else say?

Ha ha, sorry Bill you have me mis-understood! The difference in rotation is not between the DB and the Merlin but between the Hispano Suiza motor and the Merlin/DB! When the Buchon tail was re-manufactured in Spain they originally intended to stick the Hispano Suiza motor in it and they changed the careful aerofoil shape of the vertical stabiliser to help counteract the prop wash from the Suizas direction of rotation (anti-clockwise when viewed from the cockpit), however when the powerplant was later changed to the Merlin (clockwise when viewed from the cockpit) the tail designed for the Suiza was left the same! This had the effect of adding to the Yaw effect from the prop rather than reduce it, this caused the Buchon to be even more of a pig on the ground than the 109 and therefore where the stories about the difference between the handling qualities of the 109 and the Buchon come from. As you can see the problem is due to Prop rotation direction but just not how you might think it was due to!
Apologies for the confusion this may have caused!

[JDK]

Thanks for the pics, Chris!

Hope all this helps a bit.

Only if you know what you are looking at...

The break point in the radiator design is up to the 109E and the new radiator came in with the 109F onwards. All 109s have either the A-E or F-K type radiator. (It is also important to note that the Hispano Buchon has a 109G wing and wing radiator arrangement, as well as extra coolers in the nose).


A 109E. This shows the flap nicely, and through it the lower radiator flap, on the end of the small 109E style radiator housing - it's smaller all around than the F-on type.


The radiator and radiator outlet flap is nicely shown here.


Another 109E. This shows (l-r) the aileron, outer flap section and inner flap, bigger than, but over the radiator exhaust air, and below it the lower radiator flap.


This is a 109G (IIRC) and has the later style radiator. You can see how the radiator flap is much, much larger, and now fits the wing underside from the larger flatter looking radiator housing, all the way to the trailing edge. Another item not previously noted, is that the radiator inlet has a short-depth but full width adjustable lower lip, just visible here.


And this shows very clearly the way the 'old' inner flap has become the upper radiator flap and works in concord with the lower radiator flap - contrast with the first images.

WARNING!

This is a Hispano Buchon (109G wing and late type radiator, remember) with a 109E engine cowling arrangement grafted on. It's a hybrid, and there was never anything like this originally.


The poor Buchon looks very deflated, but in this shot you can see the leading flap of the radiator is a bit more open than on the 109G above.

So as we can see thanks to Chris, it's all quite simple, really, as long as you are not muddled by mongrel rebuilds.

As to the pilot/engine difference between the 109 and Buchon, another point not touched on so far is the dynamic one of the Merlin having a much higher thrust line than the DB engines, which has an effect; while there is the pilot's view in the Buchon is more restricted by the higher thrust line and 'upright' cylinder head banks than the 109 - although by the G and K, with the cannon bulges etc, that's not a huge difference.

Regards,

[JDK]

Apparently when the Spanish first built the Buchon ,they used an Hispano engine that did turn the opposite way, before converting to the Merlin. Does anyone have a good photo of one of these early Buchons that shows the prop?

Here y'go. At the Spanish Air Force Museum, Quatros Vientos.


Pretty clear cut, showing the different prop rotations. Foreground, a Hispano Ha 1112 K.1.L (note NOT a Buchón) and behind the nose of a Hispano Ha 1112 M.1.L Buchón. (the name coming from the Merlin-engine versions deep nose - like the pouter pigeon's chest, which is what a Buchón really is - see: http://palomasderaza.com.sapo.pt/buchon ... o_page.htm .)

Another pic of the 1112 M.1.L here at the top right of the Wiki page: http://en.wikipedia.org/wiki/Hispano_Av ... 3n_HA-1112

PS - I've used the correct accented term Buchón in this post, but as it is so often used by English speakers (like me) not used to the role or keystrokes for accents, it's quite common to refer to it as a Buchon - which if you were Spanish you'd pronounce differently.

Regards,

[Chris]

Thanks James. Like I said earlier, I'm not a 109 expert by any means so I didn't want to comment on anything and be absolutely wrong. I figured there was guys like you who knew more and could do a better job of explaining what is in the pics. Great job and now I'm smarter today than I was yesterday

[JDK]

Great job and now I'm smarter today than I was yesterday

Me too, except I seem to be forgetting stuff at a greater rate...

[AvroAvian]

Me too, except I seem to be forgetting stuff at a greater rate...

Oh dear! That's me too!

Great posts James and everyone else! Thanks!

[Second Air Force]

Gary A. sent me some photos of a Spanish-produced tail assembly that he was considering working on last summer. The pictures definitely show the "opposite" offset that they built into the vertical fin for use with the Hispano Suiza that rotates opposite the Daimler and Rolls.

S

[Chicoartist]

Superb thread, guys! Now, let's talk WWII 8th Air Force so I can chime in with something intelligent on the level of this discussion ~

As for the 109, Lynn Ritger has written two excellent books on the machine - I look forward to digging into them for an upcoming project - and I'd take his word on the subject as coming from the burning bush itself.

Wade

[Bill Greenwood]

If you look on the Wikipedia site for the Spanish 109, it is still claiming the D B engine turned the opposite way, "counterclockwise", which of course you can see by the photos of the props on the DB engine is not the case. The D B turns clockwise as seen from the cockpit side just like a Merlin or Allison or Pratt & Whitney or Lycoming.

The Wik site doesn't even say that the Hispano-Suiza engine turns the opposite way, but you can see by the photo of that prop that it does go counter clockwise.

So even the Wik site that is supposed to be the authority on this plane, has part of the explanation incorrect, and sort of perpetuates the myth on this.

It would be interesting to see a photo of the Hispano tail airfoil to see if one side is different than the other and form the German one.. I have never thought to look at one that closely when I was near it. Again Wik seems to have the explanation of the tail wrong, saying original 109 had this.

The original Me 109 would not have had any such asymmetrical tail airfoil for the DB, and yet it still appears somewhat difficult to handle on the ground, though this is not what the aces in 109s talk about when discussing the plane.

[Second Air Force]

I'll try to find the photos that Gary emailed me, Bill. My email account has been changed/modified since then but I may have the pictures in a file somewhere. If so I'll post them for discussion.

Scott

[Augsburgeagle]

The original Me 109 would not have had any such asymmetrical tail airfoil for the DB, and yet it still appears somewhat difficult to handle on the ground, though this is not what the aces in 109s talk about when discussing the plane.

Sorry Bill but this isn't correct, it's a bit late (2am here!) So I will post a proper response tomorrow but the 109 definitely has an asymmetrical rudder to counteract yaw and I will double check the fin is asymmetric, i'm 99% it is!
Matt

[Second Air Force]

The original Me 109 would not have had any such asymmetrical tail airfoil for the DB, and yet it still appears somewhat difficult to handle on the ground, though this is not what the aces in 109s talk about when discussing the plane.

Sorry Bill but this isn't correct, it's a bit late (2am here!) So I will post a proper response tomorrow but the 109 definitely has an asymmetrical rudder to counteract yaw and I will double check the fin is asymmetric, i'm 99% it is!
Matt

Here is the photo that Gary sent me last summer. The cleaned-up fin on the left of the photo is from an original Bf109G. The one on the right came from an HA-1112:


Look closely at the airfoil shape and you'll see that neither fin is symmetrical. The German fin is set up to assist in keeping a "normal" rotation DB powered machine flying straight, and the Hispano fin is just the opposite, correct for the Hisso that rotates CCW. I don't have anything on the rudder, but you're 100% correct on the fin, Matt.

Bill's also partly right in that Messerschmitt didn't start with the cambered fin until the Bf109F (IIRC).

Scott

P.S.

Gary apologized to me for not orienting the two fins the same direction in his photo. I pass that on to y'all, and hope it doesn't confuse anyone.

[JDK]

Thanks everyone. I make no claims to being a 109 expert, but I do know a bit about Buchons, having had an interest in it for many years...

So even the Wik site that is supposed to be the authority on this plane, has part of the explanation incorrect, and sort of perpetuates the myth on this.

I don't think anyone's suggesting Wikipedia is 'the' authority on anything, Bill. Personally, I just referred to a photo of the early Hispano-engine 109 on the page, to go with my shot. My own other shots of the K1L weren't to hand.

The reference to the meaning of Buchon (initially) is misleading also, for instance.

IMHO, Wikipedia is useful as a resource, using the references supplied, and anyone - even pilots - can edit it to correct (or otherwise) the content. Lots of people are down on Wiki, but like any tool, used properly it's good, used badly, it's misleading - even dangerous. Well referenced Wiki entries are good, use the refs - poorly or little references entries, best avoided. Just a thought.

Part of the problem here, as we are seeing, is a lack of precision in terms and aircraft sub-types referred to - which in a history like this introduces errors.

Again Wik seems to have the explanation of the tail wrong, saying original 109 had this.

Some contemporary aircraft like the Hurricane have an offset fin, others like the Walrus and Bloch 150 had offset engines. These are also often overlooked. I'd heard that the Hispano engineers reversed the 109's airfoil fin/ rudder section, but I'd always been sceptical about that, so I'm certainly interested in any further data on that. Thinking about it, given the 109's tail construction, I guess it wouldn't be too hard to reverse the airfoil, but more evidence would be welcome. [EDIT} And I see 2nd AF's posted Gary's shot - great!

Regards,

[Augsburgeagle]

Quick and Dirty shot to show the asymmetric rudder, note the rudder is slightly offset but the camera is aligned with the rudders centre, the asymmetry is clearly visible. Another subtle design feature of the 109!

[Augsburgeagle]

And for those interested a nice article about myths and facts about the 109 mainly from the Finnish side!

http://www.virtualpilots.fi/feature/articles/109myths/