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View Full Version : Difference in RL climb rate of Me-109G with gondolas?



Gaston444
11-22-2009, 05:09 PM
I was just curious about the actual difference in time to altitude of a Gustav with two 20 mm gondolas vs without them?

I know a test exists with a G-2.

Gaston

TheGrunch
11-22-2009, 05:12 PM
There's one here (http://www.wwiiaircraftperformance.org/me109/me109g-16476.html), it's for a tropicalised version, though. Another here. (http://www.wwiiaircraftperformance.org/me109/me109g-15562-mk108.html)

Gaston444
11-22-2009, 07:23 PM
Thanks!

Much appreciated! If anyone else has further links or insights on RL handling or climb effects, they are welcome...

Gaston

TheGrunch
11-22-2009, 07:34 PM
Oh, sorry, I've just realised that the second one is just a speed test. Didn't realise at first. That Mike Williams site is really quite useful, there's a lot more information on it than you'd expect to find all in the same place.

WWII Aircraft Performance (http://www.wwiiaircraftperformance.org/)

AndyJWest
11-23-2009, 04:03 AM
I wouldn't be that surprised if there were never any tests done in RL to determine this. The gondolas are clearly going to have detrimental effects on pretty well every aspect of aircraft performance, but the Luftwaffe obviously thought there was a need for them. As the links show, they made mock-ups to determine effects on speed, and knowing this they could probably make a reasonable estimate of effects on climb rate, ceiling etc, but they may well have just accepted that the plane was still useable with them, and gone into production. Knowing how slowly a plane climbs isn't going to make it climb any faster after all, and I'd think that Luftwaffe aircraft testing facilities had higher priorities.

M_Gunz
11-23-2009, 04:32 AM
Well since florettes are thrusting swords and sabres are swung in curves so that makes 109's worse at turning
than 190's, so we must realize that gondolas float and therefore they must have lifted (floated) the 109's that
had them more than a 109 without them. Of course they would also slow the 109 down since boats are slower.
If they had called them pontoons then it would have been because they made the plane more stable!

http://forums.ubi.com/images/smilies/metal.gif http://forums.ubi.com/images/smilies/53.gif http://forums.ubi.com/images/smilies/53.gif http://forums.ubi.com/images/smilies/88.gif http://forums.ubi.com/images/smilies/53.gif http://forums.ubi.com/images/smilies/partyhat.gif http://forums.ubi.com/images/smilies/53.gif http://forums.ubi.com/images/smilies/88.gif http://forums.ubi.com/images/smilies/metal.gif http://forums.ubi.com/images/smilies/11.gif

Kurfurst__
11-23-2009, 05:04 AM
Originally posted by Gaston444:
I was just curious about the actual difference in time to altitude of a Gustav with two 20 mm gondolas vs without them?

I know a test exists with a G-2.

Gaston

Well basically all the information needed is in this report:

http://kurfurst.org/Performanc...html#dragitems_table (http://kurfurst.org/Performance_tests/109G_Leistungzusammenstellung/Leistungzusammenstellung109G.html#dragitems_table)

Basically the gondolas reduced top speed at SL by -8 km/h (pure drag figure, the additional weight with gondolas complete with ammunition was 215 kg, which chopped down about another -2 km/h due to the drag, see Blatt 23). The complete report is very long, and has lots of formulas, so I did not upload it as a whole, but it gives you exact instructions how to calculate this.

Basically the Soviet tests with the 'three-gun' and 'five-gun' Bf 109G-2s (two seperate machines) are the best and easiest comparison on the effects on gunpods, if you are not into maths:

http://i38.photobucket.com/albums/e133/Kurfurst/109_stuff/Soviet_109G2_3-5gun_table.jpg

ROXunreal
11-23-2009, 05:28 AM
Do Mk108's in FW190 wings on any way decrease performance? More weight? Also there are little bumps on the wings when you carry a 108, presumably to make them fit in the wing, that affect anything?

Kettenhunde
11-23-2009, 06:00 AM
Sure, you are adding weight right?

http://img688.imageshack.us/img688/6883/fw190a8r2luftflightw.jpg (http://img688.imageshack.us/i/fw190a8r2luftflightw.jpg/)


The largest effect was on the roll rate. The FW-190A8/R2 was less agile than the FW-190A8.

Gaston444
11-23-2009, 11:15 AM
Wow! Excellent info by all concerned... The FW-190A-8/R2 chart has actually proved extremely useful in its serendipity... Special thanks to Kurfust as well: The info was exactly what I was looking for...

Kettenhunde, would it be possible for you to post a similar chart for the "normal" FW-190A-8, so that the differences with the A-8/R2 are clear?

It would be much appreciated, as I am doing some revisions to the "variants" aspect of my boardgame's Data Cards.

Thanks again to everyone.

Gaston

TS_Sancho
11-23-2009, 12:38 PM
as I am doing some revisions to the "variants" aspect of my boardgame's Data Cards.

I'm honestly curious about this. Without giving away too much, what can you tell us about what your project?

Gaston444
11-23-2009, 05:37 PM
Thanks for your interest, TS_Sancho.

It is strictly a hobby endeavor, not anything requiring copyrights...

For those who have played Avalon Hill's 1980 colour version of the old Battleline "Air Force", my version would look very familiar. The changes to the "flight models" and some rules are immense, but not those to the old game's basic maneuver mechanics.

I have to say many old-time players have felt compelled to tell me they always preferred the old Battleline "black and white" Data Cards version, which look exactly like monthly bank statements, with massive rows of indistinguishable numbers... I communicated with the actual "re-designer" of the colourized version, Kevin Zucker, and we are both equally dumbfounded at this... He did such an excellent job on this, by the way, that try as I might, I could never really improve on his basic color layout...

In any case, the amount of detail possible with even the simplified values is quite remarkable, and I think the detail "resolution" available to the game is a bit beyond what can be filled with currently available knowledge, at least for the maneuverability screen. The climb rate screen is quite precise, and you can compare and memorize the climb rates at a glance.

I can't get those PDF files to work on my post right now, but I will try to post the whole thing here tomorrow so that you can see what I am talking about.

Thanks for your interest.

Gaston

Kettenhunde
11-23-2009, 06:10 PM
Kettenhunde, would it be possible for you to post a similar chart for the "normal" FW-190A-8, so that the differences with the A-8/R2 are clear?

http://img42.imageshack.us/img42/484/fw190a8clean2.jpg (http://img42.imageshack.us/i/fw190a8clean2.jpg/)

jermin122
11-23-2009, 07:48 PM
Sure, you are adding weight right?

If I recall correctly, the weight of a MK108 and 65 rounds is almost the same as the MG151 plus 200 rounds. And the outter MG151 on A8 only has 125 rounds.

yuuppers
11-23-2009, 08:05 PM
Originally posted by jermin122:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Sure, you are adding weight right?

If I recall correctly, the weight of a MK108 and 65 rounds is almost the same as the MG151 plus 200 rounds. And the outter MG151 on A8 only has 125 rounds. </div></BLOCKQUOTE>

Weights

(MG151/20 + 140 rds) x 2 = 175.5kg

(MK108 + 55 rds) x 2 = 240kg

data from a Fw190A-8 factory data sheet

Gaston444
11-24-2009, 11:16 PM
Thanks again to Kettenhunde for the A-8 chart! Much appreciated...

Excellent reply from Yuuppers too, confirming Kettenhunde's point about the A-8/R2's roll rate, to which I would add the extra frontal 30 mm wing ammo box armor for the Sturmbocke version: Certainly such an armor plate could easily add 10-20 Kg to the 65 Kg difference in each wing, compared with the outboard MG 151 with ammo alone...

The "Sturmbock"'s turn rate was also certainly affected to some degree by all that weight, but the very small differences pointed out by Kettenhunde in speed and climb rate explain why it was still worthwhile to remove the 13 mm deck guns for the later A-8/R8: The aircraft, even as a "Sturmbock", was not a complete dogfight basket case yet...

For the Me-109G's side, note that, according to Finnish Ace Karhila, the 20 mm Gondolas affected little the low-speed turn handling of the Me-109G-6 in sustained turns, this DESPITE the noticeable effect of the 20 mm gondolas on the Me-109G's climb and roll rate: "They [other 109G pilots] usually applied full power and began to turn. In the same situation I decreased power, and with lower speed I was able to turn equally well [in a gondola Me-109G-6]."

He added (consider it is lightweight Russian fighters that are in question...): "When the enemy decreased power, I used to throttle back even more. In a high speed the turning radius is wider, using less speed I was able to out-turn him having a shorter turning radius. Then you got the deflection, unless the adversary did not spot me in time, and for example banked below me. 250kmh seemed to be the optimal speed."

This seems to indicate a much lower peak turn rate WITH gondolas than without: 160-180 MPH...

On the other hand, I think gondolas could have affected more seriously high speed handling: There is a Rall quote to that effect, and the G-6 pilot's manual indicates an extremely abrupt drop in the sustained turn rate: 180° in 13 sec. at 400 km/h, 100° in 14 sec. at 450 km/h (250 MPH)...

Yet in a "clean" Me-109G-10, the abrupt change to a nose-down trim manifests itself at 300 MPH, not 250 MPH, according to Mark Hanna...

Since at some point in the Me-109G-6's production, 20 mm gondolas were standard, and always had to be removed if the pilot wanted a "clean" Gustav, I have always wondered if they were not not in fact the main cause of this abrupt drop in the higher speed sustained turn handling, as described in these numbers of the Me-109G-6 pilot's manual.

The low-speed gondola G-6 turn rate parity with a clean G-6 seems counter-intuitive, but it does seem borne out from other accounts that the 20 mm gondolas handling effects for turns were worse at the higher speeds rather than the lower speeds...

Thanks again to everyone for all the info.

Gaston

Gaston444
11-24-2009, 11:19 PM
P.S.: I will still try posting here the Data Cards and and rules of my game soon, as there was a delay...

Gaston

Kettenhunde
11-25-2009, 05:36 AM
The aircraft, even as a "Sturmbock", was not a complete dogfight basket case yet...


Oskar Bösch did quite well in several dogfights with one.