Bf 109 F series

[Civettone]

Greg - could be that pilots very familiar with the 109 were solicited. If so, the discussion is always "if we do that, the other thing won't be quite as good" or "production re-tooling to change wing design is XX months" or "add this and your climb rate will be yy less"

BTW - if you move the gear - it has to re-located to main spar or create a major carry through Structure just aft of the leading edge "d' box is.. last - to do so means a major re-design for fuselage carry through structure if wings are to be made 'removable' as before.

MAJOR re-design and significant weight increase - look to Milosh's post 88 for closer inspection.

I completely agree! I think it is very easy for us to assume the role of the all-knowing-aeronautical-engineer, but we have to assume the designers/engineers knew what they were doing. If they would be with us, they could probably come up with a dozen objections to the things we propose. I think we should be very careful and above all, modest about what we think should have been done.


Kris

 

[jim]

Often even engineers disagree between them about what s good.
I have read somewhere that when some german enginners saw the spanish 109s with the internal wing cannons critisized the choise for weakening the wing.. Who was correct? Who knows...
Mr Greqp
Do you believe that there was space for improvement in the wind screen section of the 109? Impropvement that would bring speed benefit?

 

[GregP]

There certainly IS space and it would certainly improve the view. Whether or not it would result in any speed increase depends on the entire cockpit canopy, not just the windscreen.

For best streamlining, the height of the canopy above the fuselage should be about 1/3 or less of the horizontal length of the windscreen and the sliding (or swining as the case my be) part of the canopy enclosure needs to be at least 3 times the horizontal length of the windscreen. Any shorter and drag starts to increase. What that tells me is that there SHOULD be a slight decrease in windscreen drag with a new canopy.

How much speed difference it would make is dubious and would have to be determined in a wind tunnel or on an aircraft. If there was an increase, it would be slight ... on the order of a few knots, maybe even 1 or 2 knots.

My chief concern would be to make the canopy frames as small as possible and to fit a bubble-type canopy enclosure ... for the purpose of improved visibility, not for any speed increase which, though small, would be welcome I'm sure ... if it was noticed at all by the fliers.

When I go into the Museum Saturday, I'll make sure to charge my camera and get some landing gear shots and some canopy shots. I'll post them in here Saturday or Sunday.

 

[silence]

How about going back to a canopy with rounded rather than angled edges, a la the Emil? I read somewhere that sharp angles produce a lot more drag (this was an issue with the old Lamborghini Countach, as I remember). Or a Erla canopy with rounded edges and the armored glass headrest thingy. At least then you'd get some improved vision without having to redesign the fuselage, too.

Not sure if the drag saved is significant, though. But, yeah, gotta get rid of those prison bar frames.

 

[GregP]

The windscreen was awful. The canopy, while not my favorite by any means, isn't bad except for rearward visibility.

I have sat in Bf 109 / Ha.1112 cockpits for some time while working on them. The visibility forward and I mean directly forward is OK. Anything to the side, even slightly, is almost blind. Terrible except directly forward.

That's what I would change before anything else. I'd also put in a curved windscreen bow, meaning a new tilting or sliding canopy, too ... as a result of the curved windscreen bow. Don't even tell me they couldn't do it. Go look at an Me 163B or an He 100 or even an Me 262, which has a decent windscreen with small frames and is very close to a P-51 windscreen.

 

[stona]

The problem with visibility is not just the canopy design, framework etc. The cockpit is very narrow. It is so narrow at shoulder height that it is almost impossible for an man of average build to turn to look behind (assuming the view is going to be anything but armour plate), unless his neck operates like the girl in "The Exorcist" . Behind is where the most immediate danger is likely to come from. I know because I've tried. That is not an easy fix.

There is an old joke that evasive action in a P-47 meant running around in the cockpit, not an option in a Bf 109

Cheers
Steve

 

[GregP]

True ... it IS narrow, but not so much unless you're sitting on a parachute as in combat. If you are, it IS narrow. If you aren't it is ... OK. If you are face down with your feet sticking out trying to bolt in the landing gear brackets on the inside of the firewall, it is absolutely insane. Been there, done that ... no thanks again.

I don't really see the narrowness as an issue, but I was sitting in it without a parachute on the ground ... not in the air WITH a parachute at 5+ g. In that situation, I can see the issue. The solution is a slightly shorter stick with more mechanical advantage and relocated tabs for the control cables. VERY possible ... might need thicker elevator and aileron skin or at least doublers.

I have also sat in a replica Caurdon C.460. The cockpit is as narrow as your head ... without a helmet. Very claustrophobic and very likely to kill you if ANY impact happens. But ... a decent-flying aircraft to hear Mark Lightsey tell it (the builder and pilot).

I have an offer to get into the cockpit of a flying de Havilland Comet replica and will DO it when I get the chance.

 

[drgondog]

Greg - you're designing in a 'no amateur' zone and making suggestions based on your observations - not facts or design approach based on facts and choices based on facts. The 109K was a derivative of the original 109 with few external/internal changes regarding layout of critical components such as cockpit dimensions, control surfaces, control links, seat arrangements, etc.

Your assumptions of "VERY possible" are based on your limited knowledge of the specs, the data, and the reasons for the design questions and ultimate design decisions. In essence you have declared victory based on your opinions versus some of the finest airframe design engineers in the world.

Good luck with that.

 

[GregP]

Thanks Drgondog for the "good luck" encouragement.

You are pontificating based on no design work on improvements to the Bf 109 at all. Doing no redesign is easy. Coming up with "fixes" isn't quite as simple but is way more fun. None of my suggestions for the Bf 109 were taken to final design stage, they were suggestions on a way to go to help fix some shortcomings back in the day, not complete redesign plans and drawings complete with stress analyses. If I had a Bf 109F today, it would have a modern panel, but the rest would be as stock as possible.

I have participated in the redesign of several items on our YP-59A Airacomet including design and fabrication of a completely new sliding canopy that is now on the plane and helping with changing the trim tabs into boost tabs on the ailerons. I am now working on adding an external canopy crank that doesn't protrude into the airstream. I also designed and fabricated the sheet metal to keep water out of the cockpit when we wash it and was half of the team that made a new windscreen bow when the old one was shown to be insufficient.

So far, all of the projects I have worked on as "fixes" are on planes that are flying (includes a Vought Corsair and a Northrop N9M-B Flying Wing) or still in restoration to fly in the future (includes a Bell YP-59A, a North American O-47, a Yokosuka D4Y Judy (static on purpose), an Aichi D3A Val, and modifications to one of our AT-6's). I've also done several mods to a freind's RV-7 at his request. It flies frequently.

I was one of three guys who restored a WW2 pulsejet to running condition. You can see it if youi Google "Chino Pulsejet." The gray Nissan Titan being pushed down the runway is my truck. That was an entire exercise in "fixes" and there was no manual. Took 2 years but was worth it.

Sorry you have such a low opinion of my general suggestions. Glad other people don't or I wouldn't have so much fun doing it every weekend. Some of my Bf 109 suggestions would be fun to put on our Hispano Ha.1112, but the objective is to make it back into a stock Hispano, not modify it into something that never flew operationally. We're well along with it now. Most of the Hispano mods have consisted of going to SAE hardware where practical but I did rebuild one wood structure for a radiator by simply duplicating the shape of the deteriorated unit.

Good luck to you, too, guy.

 

[drgondog]

Greg - have you given any thought to the enormous leap to go from piddling around with restoration of an existing airframe to analyzing the implications of making major re-design decisions affecting tooling, spares, production efficiency?

Sometimes good ideas for incremental improvements are discarded primarily for one or more of the factors above.

As to being 'sorry', you shouldn't care for my opinion one way or another..

 

[drgondog]

Thanks Drgondog for the "good luck" encouragement.

You are pontificating based on no design work on improvements to the Bf 109 at all. Doing no redesign is easy. Coming up with "fixes" isn't quite as simple but is way more fun. None of my suggestions for the Bf 109 were taken to final design stage, they were suggestions on a way to go to help fix some shortcomings back in the day, not complete redesign plans and drawings complete with stress analyses. If I had a Bf 109F today, it would have a modern panel, but the rest would be as stock as possible.

Good luck to you, too, guy.

I forgot to comment on this pearl of wisdom.

You also seem to struggle a little bit with how design mods work.
1.) Customer requests the change.
2.) Airframe group analyzes and proposes changes to a.) airframe, b.) effectivity, c.) non-recurring costs to make and implement the change, d.) unit price change for new version (which includes tooling, space on the line, re-training, communication and on-going support)

It usually Doesn't originate from a bored engineer flipping paper clips into the ceiling, and in times of war - always originates and receives approval (funded) from the customer after being blessed by Company management team including the Chief Designer, the Chief Manufacturing, the CFO and CEO.

I'm happy for your experience and skills as a restorer. While my experience at Lockheed and Bell as design, preliminary design, airframe structures and manufacturing Liaison engineering and project management may not qualify in your mind as one to comment on your vocalized thoughts...?

Oh, well I can live with that.

 

[GregP]

Not being in the design end of an aircraft production staff, I don't care one way or the other myself. The thread went toward suggesting improvements for the Bf 109F and I went with it. This forum, for me anyway, is for exchanging information and for fun ... not for completed redesign plans. All my suggestions would have been run through the Messerschmitt design staff had I been there, not done on a one-or-two basis. Some were simple, like adding a rudder trim tab. That's almost a no brainer and should have been there from the start. Brain fart on Willy's part.

Others would have taken some time, like moving the landing gear. I think they should have done so and early on, even before they were sent to Spain. Obviously you think the Bf 109 was fine the way it was. In the end, so did Willy since the changes were never done. That doesn't leave much room for discussion about changes, does it?

Viva la difference.

I have regard for your opinion, but not so much when it is cached in sarcasm or insult ... much more so when it is given objectively and constructively.

Cheers.

 

[GregP]

I was primarily in the electronics industry (electrical engineer) after changing from aeronautical engineering in my junior year. We had procedures, too, for changes that ran about as you describe above.

But when WE were the design agency (like Messerschmitt was) and had suggested improvements, we suggested them together with NRE and all costs. Sometimes they were accepted and sometimes not. If the product was ours, we suggested to an internal staff and the suggestions were either accepted or rejected based on incremental cost and break-even time. I believe we have already touched on whether or not the Nazis would approve any Bf 109 changes. It appears they might not have approved any changes.

So don't go thinking that you were alone in management or engineering. There are LOTS of us out there. I'd bet a good deal that we have 25 or more managers or former managers in here who can write out a change process easily and can do a cost breakdown. As far as that goes, the cost would be minimal if done while the planes were in production, but would be more expensive if retrofitted.

I'd have gone with the changes in the production phase and lived with the existing aircraft.

Enough about us and the change process, let's get back to the Bf 109F, OK?

Great plane with some flaws ...

 

[drgondog]

Yawn

 

[razor1uk]

I think their is some kawasaki green-ness building to a fire risk soon here...

 

[GregP]

Back to the Bf 109 after a brief stopover in the "who can piss farther into the wind" zone. I have to let that go or it escalates and somebody gets wet. I seem to recall a warning before on it, so I give.

I went to the Museum today and got some pics so we can see what we are talking about. Below is a pic of the firewall and gear brackets. You can see the bottom of the fuselage oval has a more or less straight piece in it and the gear bracket is attached to both the fuselage and the firewall at a 90° angle and is bolted from both directions. There are also bracket backings inside the cockpit.

You can see there's room along the bottom of the firewall for a stub spar across the botttom to extend the gear to the end of a stub wing. The gear alignment adjusters are easily adjusted and locked in place but they can't be adjusted for alignment except to make the gear leg fit into the wheel well. The drag links set the wheel alignment and are are cast into the upper gear leg.

As you can probably tell, these aren't Bf 109 tires. While we are working on it we have MiG-15 tires fitted since we have them and they fit.

I thought the pics would make it more clear.

Here is some eye candy. While I was there they were rolling out Race 232 for the first pre-Reno 2013 test flight. We filled the boil-off oil cooler with ADI (water-methanol) and fueled it. The test fight will probably take place tomorrow or Monday.

Race 232 finished second at Reno last year in the Unlimited Gold class, but Rare Bear is back WITH sufficient cooling, Strega is back and Voodoo is back, so poor old 232, with a quite stock R-3350 of about 3,600 HP, will be lucky to be fourth unless someone breaks. Of course, I'm pulling for Stevo Hinton Jr, in Voodoo. Go Stevo!

Here's a clip of Race 232 when it was September Pops:


View: https://www.youtube.com/watch?v=wMPdV6xA8X0

In case anyone is wondering, the R-3350 is an 18-cylinder engine and there are 9 exhaust pipes on each side.

 

[GregP]

Here is the rear access hatch. Believe it or not, I've been in there myself! Tight fit for me. The second pic down is looking forward inside the access hatch. As you can see, there is plenty of room for slightly more fuel right there.

The bottom curved parts of the bulkhead are where the Oxygen tank would go, but there IS enough room for extra fuel to a point.

 

[Tante Ju]

GregP, thank you for posting these wonderful detail pictures!

 

[GregP]

You're welcome.

If you have any requests, I can take pics. Look at the Planes of Fame website. Many of the planes are at Chino while some are in Arizona. I can get any detailed pics of the Chino planes easily and will post if asked specifics. For some, I can get cockpit pics ... but not for all. Some of the planes are owned by private owners and we can't get on them to get cockpit shots.

Here's a shot of the bottom front right of the cockpit of the Ha.1112. Everything has been removed or you'd see the rudder pedals near the landing gear backing brackets. The nuts you see at the bottom are actually at the top of the landing gear mounting brackets, so the stresses are carried by about half of the firewall-fuselage joint.

You can probably see the bolt pattern matches the upper landing gear mounting bracket in the second bracket pic 2 posts above. The entire cockpit has been cleaned out and we are starting on the new instrument panel now. We have SOME original instruments, but also have some USA-required instruments that have to be there to get an airworthiness certificate in all practicality.

Altimeter and airspeed come to mind. They need to be in feet and knots to fit in with air traffic control and avoid overspeeds below 10,000 feet, which the Ha.1112 is easily capable of.

 

[GregP]

I mentioned in my rant above with Drgondog that I had made a new canopy for the Bell YP-59A. Here is a pic of it sitting backwards on the starboard wing:

The people involved were me, Greg Pascal, Bob Velker (the defacto leader), and Fran Pieri (former B-47 pilot and American Airlines Captain). Below is the method we came up with to hold the canoy on the plane in flight. I'll get a shot of it when the emergency release handles are in place the next time we put the entire canopy together. Yo0u can see the sheet metral doesn't exactly fit the windscreen near the top ... but it WILL when we're done. Just a bit more ""persuasion" is required.

We made the emergency release mechanism from a milled-down Grumman F8F Tigercat emergency release mechanism. It was about .025 inch too wide so we milled it down so it would pass the structure. Seems to work just fine.

I also said we made a new canopy bow. Here is a pic.

We modeled it out of balsa wood, went and got a 6-inch cylinder of 7075 Amuminum, cut it in half on a BIG bandsaw, sculpted the bow on a mill, and sanded it to exactly conform to what we needed. Solid and not too heavy. Besides which, we'll need about 1,000 pounds of lead in the nose anyway to make up for the lack of guns, so 4 pounds or less isn't excessive.

Nothing to do with a BF 109F but seemed relevant to thread development so I don't come across as a bullsh*tter. I am one of about 300 volunteers who get it done for the Planes of Fame.