Author Topic: 109 performance notes  (Read 6406 times)

Offline Kurfürst

  • Parolee
  • Silver Member
  • ****
  • Posts: 921
      • http://www.kurfurst.org
109 performance notes
« Reply #75 on: November 16, 2005, 03:40:42 AM »
Quote
Originally posted by gripen
All you need to do is find a Mtt paper (Datenblatt, errechnete werte) dated 12.5.1942 (among same set as GL/C-E data) and it claims 732 km/h at 7500m (DB 605A, Start- und Notlstg.).

gripen


You can give the exact reference to the microfilm and archive so I can find it. Of course, IF you actually have this document. You can reproduce it here if it exists to see what it exactly says, what conditions for the aircraft, and what corrections were or were not made to the data.

732 kph is otherwise very reasonable speed for the 109G-1. The G-1 was rated 650 kph in its official kennblatt with 1,3ata, and with Startleistung 685kph. That's the official data, like the G-14 ones. If you don't like it, come up with your own sources.

GM-1 injection which all G-1s had as standard fitting added 300 HP to the engine, and added 120 km/h to the topspeed roughly 1,5km above rated altidude, which just happens to fit. With GM-1 the DB605A's output was ~1100 HP at 10km, slightly better than the RR Griffon 65. I don't see why the considerably slower 109G with more power would not attain similiar speed than the SpitXIV.
The Messerschmitt Bf 109 Performance Resource Site
http://www.kurfurst.org

Offline Angus

  • Plutonium Member
  • *******
  • Posts: 10057
109 performance notes
« Reply #76 on: November 16, 2005, 03:54:36 AM »
That speed is ....whooping!
It was very interesting to carry out the flight trials at Rechlin with the Spitfire and the Hurricane. Both types are very simple to fly compared to our aircraft, and childishly easy to take-off and land. (Werner Mölders)

Offline gripen

  • Silver Member
  • ****
  • Posts: 1914
109 performance notes
« Reply #77 on: November 16, 2005, 04:19:30 AM »
Quote
Originally posted by Kurfürst
You can give the exact reference to the microfilm and archive so I can find it. Of course, IF you actually have this document. You can reproduce it here if it exists to see what it exactly says, what conditions for the aircraft, and what corrections were or were not made to the data.


Well, it's among the same set as other papers posted in this thread but to save some your work, here it is. I'm sure that Pyro will take it just as seriously as above posted data.

gripen

 

Offline Crumpp

  • Parolee
  • Gold Member
  • *****
  • Posts: 3671
109 performance notes
« Reply #78 on: November 16, 2005, 04:24:10 AM »
That document is unreadable.

All the best,

Crumpp

Offline gripen

  • Silver Member
  • ****
  • Posts: 1914
109 performance notes
« Reply #79 on: November 16, 2005, 04:32:05 AM »
Hm... the type of the plane, speed values, weight, the type of the engine, setting of the engine etc. All are readable.

gripen

Offline BlauK

  • Platinum Member
  • ******
  • Posts: 5091
      • http://www.virtualpilots.fi/LLv34/
109 performance notes
« Reply #80 on: November 16, 2005, 06:48:46 AM »
gripen,
what IS that plane type? Does it say 500 rounds for the 1 x MG 151?
Is that some kind of spec sheet for some concept?


  BlauKreuz - Lentolaivue 34      


Offline Porta

  • Zinc Member
  • *
  • Posts: 39
109 performance notes
« Reply #81 on: November 16, 2005, 07:13:06 AM »
The details of the plane (Bf 109 G-1 Endzustand) used for those calculations are shown in sheet IV/31/42. It includes the following improvements over the standard calculated performance of G-1:

- Wheel well doors
- Radiator flaps with improved kinematics
- Surfaces specially treated

In adition, the coolant relief valve setting in VDH is raised to 1,3 to 1,5 atü (standard was 0,75 atü), and the oil cooler intake is also improved.

Another history would be if the calculated performance of the basic G-1 was OK or not...

Offline Crumpp

  • Parolee
  • Gold Member
  • *****
  • Posts: 3671
109 performance notes
« Reply #82 on: November 16, 2005, 08:20:42 AM »
Quote
The details of the plane (Bf 109 G-1 Endzustand) used for those calculations are shown in sheet IV/31/42. It includes the following improvements over the standard calculated performance of G-1:


There is your explanation, Gripen.  I have FW-190 flight-tested performance that gives 700kph at 2nd Gear FTH.  The same aircraft is also much slower at sea level.

Hardly typical but well within manufacturers guarantee.

For what it is worth:

German flight testing procedures tend to follow a different format than the allied ones for standard production performance in my experience.  While the allies tend to test one or two aircraft producing a report specific to that serial number, the Germans tended to test multiple aircraft over several hundred flights.  This can be seen in the Me-262 report posted in this thread.

They then produce a general report describing the average performance and specific aircraft set up used.  Mtt will publish calculated figures included in this report as well many times.  Focke Wulf does not usually include calculations in the report.  A flying schedule and list of pilots and aircraft flown can sometimes be found as an appendix or referenced as a separate report in the case of Focke Wulf, Gmbh.

Focke Wulf produces the calculation reports separately from the flight test as well.  These calculations tend to be extremely detailed and all the reports I have for FW-190V5g thru FW-190D15 are several hundred pages of calculations.  For example the calculation report for the FW-190A8 are over 500 pages.  Calculations are also very distinctly labeled as such.

Mtt will almost always include general calculation sheets as well in flight test reports:

http://www.beim-zeugmeister.de/zeugmeister/index.php?id=28&L=1

As a general trend, calculations tend to be conservative and not optimistic in any aircraft manufacturer.  It is just simple economics.  Everyone comes out a winner with conservative estimates and everyone looses with optimistic ones.

All the best,

Crumpp

Offline Angus

  • Plutonium Member
  • *******
  • Posts: 10057
109 performance notes
« Reply #83 on: November 16, 2005, 08:22:37 AM »
I can read that document but it could do with a tad of photoshopping.
Interesting stuff.
It was very interesting to carry out the flight trials at Rechlin with the Spitfire and the Hurricane. Both types are very simple to fly compared to our aircraft, and childishly easy to take-off and land. (Werner Mölders)

Offline Crumpp

  • Parolee
  • Gold Member
  • *****
  • Posts: 3671
109 performance notes
« Reply #84 on: November 16, 2005, 08:24:52 AM »
Quote
Hm... the type of the plane, speed values, weight, the type of the engine, setting of the engine etc. All are readable.


If that is all the detail you focus on, Gripen, then you will draw an inordinate amount of erroneous conclusions.

All the best,

Crumpp

Offline gripen

  • Silver Member
  • ****
  • Posts: 1914
109 performance notes
« Reply #85 on: November 16, 2005, 09:18:33 AM »
Quote
Originally posted by Crumpp
If that is all the detail you focus on, Gripen, then you will draw an inordinate amount of erroneous conclusions.


I wonder what you might mean, I have not made any conclusions here, merely posted a datasheet from Mtt.

gripen

Offline Bruno

  • Silver Member
  • ****
  • Posts: 1252
      • http://4jg53.org
109 performance notes
« Reply #86 on: November 16, 2005, 11:01:16 PM »
From an old post on LEMB

Quote
BPNZ

Hi Everyone,
I've got a data chart showing the G14 having the same speed as the G6/R2, both with DB605AM engines:

568km/h (353mph) @ SL
665km/h (413mph) @ 5000m

Felix99

From Datenblatt A/IV/141/44, and charts A/IV/142/44 and A/IV/144/44, for the G-14/U4 w. 605AM

At Take-off and Emergency setting:
557km/h (346mph) @ SL
652km/h (405mph) @ 5000m

At Climb and Combat setting:
486km/h (301mph) @ SL
619km/h (384mph) @ 6600m
« Last Edit: November 16, 2005, 11:04:27 PM by Bruno »

Offline elkaskone

  • Zinc Member
  • *
  • Posts: 17
109 performance notes
« Reply #87 on: November 17, 2005, 12:27:38 AM »
Hi Bruno,

on your second 109G14 Dokument is there a weight indicated?
Maybe the slower speeds are with Mg151/20 gondolas?!

The first Document i now its a clean 109G14-U4 with 3318kg!

Offline Kurfürst

  • Parolee
  • Silver Member
  • ****
  • Posts: 921
      • http://www.kurfurst.org
109 performance notes
« Reply #88 on: November 17, 2005, 04:07:46 AM »
Quote
Originally posted by Porta
The details of the plane (Bf 109 G-1 Endzustand) used for those calculations are shown in sheet IV/31/42. It includes the following improvements over the standard calculated performance of G-1:

- Wheel well doors
- Radiator flaps with improved kinematics
- Surfaces specially treated

In adition, the coolant relief valve setting in VDH is raised to 1,3 to 1,5 atü (standard was 0,75 atü), and the oil cooler intake is also improved.

Another history would be if the calculated performance of the basic G-1 was OK or not...



Oh, that makes it clear... gripen was telling half the truth it seems. Rechlin was regularly suggesting possible improvements to the manufacturers about how to improve plane performance, sometimes these were introduced, other times - not. The 109G was originally planned to have well doors, but in the end only a few got them. Just check a 109F wheel well, it's circlur, while the 109G had staight panel towards the wingtip - that's where the wheel well door would have been fitted.

Porta, do you have the complete report? I'd be interested, I've got a lot of 109 stuff, I'll see what I can give you in exchange. My email is kurfurst@atw.hu !

BTW, Leistungzusammenstellung for the 109G notes +10kph for the well doors, +12 for improved finish at SL. That's +22, and to adjust it to the VDH, alone these changes would result  +35, plus the other we dont know how much it would worth.
The Messerschmitt Bf 109 Performance Resource Site
http://www.kurfurst.org

Offline gripen

  • Silver Member
  • ****
  • Posts: 1914
109 performance notes
« Reply #89 on: November 17, 2005, 04:42:31 AM »
Quote
Originally posted by Porta
The details of the plane (Bf 109 G-1 Endzustand) used for those calculations are shown in sheet IV/31/42. It includes the following improvements over the standard calculated performance of G-1:

- Wheel well doors
- Radiator flaps with improved kinematics
- Surfaces specially treated

In adition, the coolant relief valve setting in VDH is raised to 1,3 to 1,5 atü (standard was 0,75 atü), and the oil cooler intake is also improved.

Another history would be if the calculated performance of the basic G-1 was OK or not...


Using Raunios article and MT-215 data as a baseline, 636 km/h at 6400 m (couple km/h could be added for the slightly lower rpm than the spec):

Tailwheel 10 km/h
Wheel doors 10 km/h (Raunio gives 5 km/h but Mtt test data about 10 km/h)
Polished surfaces 15 km/h

Can't say much about the kinematics of the radiators and oil cooler intake but these were in shut position on the MT-215 speed runs anyway. That will result about 670 km/h somewhere around 6600-6700 m assuming no losses on the propeller. Propeller efficiency curves for 6000 m (both, by Mtt and Raunio) give about 2-3% decrease from 640 to 670 km/h so in practice something around 660 km/h at around 6700 m would have been reachable at 1,3ata 2600 rpm, while the datasheet claims 707 km/h at 7500m. Correcting the FTH to 6700 m for the datasheet gives about 695 km/h so a quick and dirty analysis gives roughly 35 km/h difference between practice and calculation.

gripen
« Last Edit: November 17, 2005, 04:49:12 AM by gripen »