Engine Gap Seal

[USARStarkey]

So is the new 190D modeled with a engine gap seal or not? No Production D-9 ever had one, and it makes a huge difference in performance.

[ARM505]

Can you elaborate? I know what they are and do, just can't really figure out where they would put one in a 190D? And why the gains would be so big?

[USARStarkey]

because the real Dora did about 415mph, as the without the seal it it caused alot of drag.

[Krupi]

According to my sources...

 

Fw 190 Volume 1

 

[ARM505]

Without debating what the exact speeds were, I'm curious as to what gap was sealed. I'm aware of performance packages for modern aircraft (for example flap gap seals, sealing door lines etc in 172's etc) but I don't know what or where the 'engine gap' in a 190D would be?

[Narushima]

Without debating what the exact speeds were, I'm curious as to what gap was sealed. I'm aware of performance packages for modern aircraft (for example flap gap seals, sealing door lines etc in 172's etc) but I don't know what or where the 'engine gap' in a 190D would be?

 

I think it's referring to the gaps around the exhaust vents. Just my opinion though, can't back it up with evidence.

 

As for the performance increase, it was around +10km/h top speed, give or take some depending on altitude.

[theChris]

Also based on the manual the fw-190 we are getting has the semi retractable tail wheel. Adds a significant amount of speed.

[USARStarkey]

So the engine gap seal was a feature not installed on production D-9s. It was declined due to rubber shortages. The 420+ figure quotes for the D-9 assumes the seal was installed.

 

http://www.wwiiaircraftperformance.org/fw190/fw190d9test.html

 

Read above if your interested.

 

http://imgur.com/jy5vBGW

 

above includes the seal.

below is from flight trials without the seal.

 

http://imgur.com/3fY9z9K

 

 

"Lutz Naudet placed these performance trials in context:

 

Now lets come to the interpretation as to why both Wk.-Nr. 001 & 002 generally fall short of calculated values. The first problem with all flight trials of Wk.-Nr. 001 & 002 is that they were done with the initial batch of production engines, which have well documented problems with supercharger performance. Those first production engines produced 60-100PS less than the book values used for performance calculations. The second problem is the engine gap. The drag data for the D9 most likely comes from scale models; those models will not have the engine gap as they are "carved out of one piece of wood". The scale model, therefore, has a smoother surface than the real airplane. The speed increase in the tests, where the gap was sealed, support this assumption. Nevertheless, the tests are representative of performance for operational Fw 190 D9s. As best as can be determined, the engine gap seal was never introduced into serial production due to rubber shortages. It should be noted however, that operational planes with a good surface finish and an engine running to book values will perform better than both Wk.-Nr. 001 & 002. This is supported by the few speed runs with the JUMO 213A tested on the bench.

 

Now lets examine the “Erhöhte Notleistung” and “MW50” speed runs. When looking at the results, we must keep in mind that Wk.-Nr. 002 was specially rigged for those runs to enable the testing of both settings in one airplane. Wk.-Nr. 002 engine installation was therefore not in a standard production condition when carrying out those speed runs. Standard production planes had either “Erhöhte Notleistung” or “MW-50” available, not both. The surface finish and other equipment of Wk.-Nr. 002 during this test is the equivalent of a standard production plane. Report #2 focuses on the speed increase through “Erhöhte Notleistung” and “MW-50” compared to Take-Off/Emergency rating. Report #3 examines in detail the speed increase from sealing the engine gap, but the tests were only carried out up to 3,6km. The bottom line for those reports is that they provide us with a good overview of how the “Erhöhte Notleistung” or “MW50” boosted performance, but only up to ~3,6km. The speeds attained, without engine sealing, between SL and 3,6km can be considered representative for operational aircraft."

Edited August 6, 2014 by USARStarkey

[ARM505]

Thanks, nice links and info in general.

 

Program:

 

1. Determination of the gain in speed in flight, with increased Take-off and Special Emergency Power, by seals at the engine gap.

2. Check of the flight characteristics with Verkleidung für Bildgeräte Schrägeinbau.

 

Results:

 

1. As delivered, substantial gaps were present at the engine, in particular in the transition from the cowl to the wing. In order to check for their influence on level speeds, performance comparison flights were carried out in the low supercharger range, before and after sealing of all existing gaps.

 

After conclusion of the trials in the initial condition, an even gap width at the transition from the cowl to the wing had to be ensured, first by shifting of the lower engine cover against the propeller direction of rotation, since substantial differences arose by the engine torque in flight. Then the sealing of the fairing was made by means of rubber gaskets and metal strips.

 

The enclosed speed graph shows level flight performance with Increased Take-off power (1900 HP - basis) and Special- Emergency power. As evident, a gain in speed of 13 to 15 km/h is obtained by the gap sealing. Level speeds at Sea Level:

 

Without gap sealing: Take-off power VwKC = 346 mph

Increased power VwKC = 357 mph

Special Emergency Power VwKC = 370 mph

 

With gap sealing: Take-off power VwKC = -

Increased power VwKC = 366 mph

Special Emergency Power VwKC = 378 mph

 

During these flights the seals between engine and wings pulled out and then were torn off. It was also noticed that exhaust gases caused minor fire in spots. Therefore, an improvement of the sealing within this area is necessary.

 

[otto]

I'm sure that ED has much better documentation, data than ww2aircraft performance site.

And they are going to model the engine gap seal or lack of properly.

 

But i just don't trust that ww2 performance site.

 

Every comparison chart is set in such a way that spitfire always seems faster , better.

For example 109 g6 vs Spit 9 . 109k vs spit 14.

 

Where is the 109 G 14 , G6 AS vs spit 9 ? 2 planes the spit 9 would surely met in combat.

Where is the 109 K vs spit 9 ?

There weren't a lot of spit 14's flying around. Not nearly as much as spit 9's.

 

 

And that site had so many translation errors for a site that should present accurate info.

[MiloMorai]

I'm sure that ED has much better documentation, data than ww2aircraft performance site.

And they are going to model the engine gap seal or lack of properly.

 

But i just don't trust that ww2 performance site.

 

Every comparison chart is set in such a way that spitfire always seems faster , better.

For example 109 g6 vs Spit 9 . 109k vs spit 14.

 

Where is the 109 G 14 , G6 AS vs spit 9 ? 2 planes the spit 9 would surely met in combat.

Where is the 109 K vs spit 9 ?

There weren't a lot of spit 14's flying around. Not nearly as much as spit 9's.

 

And that site had so many translation errors for a site that should present accurate info.

 

Spit 9s shot down a Me262 so other Me types should be no problem.

 

Yes, the truth can be hurtful.

 

So why don't you contact Mike with the translation error corrections?

[9.JG27 DavidRed]

Spit 9s shot down a Me262 so other Me types should be no problem.

 

Yes, the truth can be hurtful.

 

So why don't you contact Mike with the translation error corrections?

 

totally depends on the pilots...some lose dogfights in F15s against p51s...and take my word, many will lose dogfights against 109s and 190s no matter the fuel type, ammunition, engine gap seal or not...yes truth can be hurtful

Edited August 6, 2014 by 9./JG27 DavidRed

[USARStarkey]

I'm sure that ED has much better documentation, data than ww2aircraft performance site.

And they are going to model the engine gap seal or lack of properly.

 

But i just don't trust that ww2 performance site.

 

Every comparison chart is set in such a way that spitfire always seems faster , better.

For example 109 g6 vs Spit 9 . 109k vs spit 14.

 

Where is the 109 G 14 , G6 AS vs spit 9 ? 2 planes the spit 9 would surely met in combat.

Where is the 109 K vs spit 9 ?

There weren't a lot of spit 14's flying around. Not nearly as much as spit 9's.

 

 

And that site had so many translation errors for a site that should present accurate info.

 

 

G-6AS as made in tiny numbers (like 600) and the G-14/AS didnt come out until September 44 and was only a quarter of G-14 productions. They are both either too little or too late, and therefore have no place in a general comparison to the spit 9

[USARStarkey]

totally depends on the pilots...some lose dogfights in F15s against p51s...and take my word, many will lose dogfights against 109s and 190s no matter the fuel type, ammunition, engine gap seal or not...yes truth can be hurtful

 

I think it's pretty obvious, emoticon and all, that he was making a joke regarding the 262 bit.