DCS: de Havilland DH.98 Mosquito FB Mk VI Discussion

On 8/13/2021 at 7:35 PM, rkk01 said:

Can anyone enlighten me on Mosquito exhausts???

 

The 10 saxophone exhausts on the FB.VI struck me as odd on a 12-cyl engine…

 

A quick look through photo-refs suggest the unshrouded B-models have 6 per side and the FB-models 5 per side

Apparently, those last two pipes were merged (as shown on SMH's photograph) to avoid the gas heat from damaging the wooden structure of the wing. But I could not find a valid reference to confirm that.

It seems to make some sense, though I'm not entirely convinced it'd change anything. Perhaps it could be an issue when running idle, but it could also be designed that way because there was not much room for a 6th pipe at the back of the engine assembly.

On 8/16/2021 at 8:40 AM, Redglyph said:

 

Apparently, those last two pipes were merged (as shown on SMH's photograph) to avoid the gas heat from damaging the wooden structure of the wing. But I could not find a valid reference to confirm that.

 

It seems to make some sense, though I'm not entirely convinced it'd change anything. Perhaps it could be an issue when running idle, but it could also be designed that way because there was not much room for a 6th pipe at the back of the engine assembly.

Also remember, the Spit V and earlier had shared exhaust stacks for each cylinder.

What the advantages/disadvantages are and and why they changed, I don't know. I think some of it was trying to squeeze a tiny bit of extra thrust out of the stacks.

Oddly the earlier Mosquito bomber variant seems to have 6 individual stacks per side. They're often covered by a flame dampener too as they were night bombers. I've been wondering forever why the FB had two shared but I've never gotten a convincing answer for it. (And it's also quite possible there's no real reason at all. Could just be that's how that particular model of Merlin engine came.)

3 hours ago, SMH said:

Also remember, the Spit V and earlier had shared exhaust stacks for each cylinder.

What the advantages/disadvantages are and and why they changed, I don't know. I think some of it was trying to squeeze a tiny bit of extra thrust out of the stacks.

Oddly the earlier Mosquito bomber variant seems to have 6 individual stacks per side. They're often covered by a flame dampener too as they were night bombers. I've been wondering forever why the FB had two shared but I've never gotten a convincing answer for it. (And it's also quite possible there's no real reason at all. Could just be that's how that particular model of Merlin engine came.)

The two-stage chargers Merlins were installed a little more forward of the wing than the single stage Merlins. As a result, there was room for a 6th exhaust stub. The variants with a single stage Merlin had 5 stubs because the 6th was thought to be too close to the wind leading edge and may damage it.

Merlins 21, 23 & 25 used in the FB.VI were single stage, hence 5 stubs. 

37 minutes ago, Bozon said:

The two-stage chargers Merlins were installed a little more forward of the wing than the single stage Merlins. As a result, there was room for a 6th exhaust stub. The variants with a single stage Merlin had 5 stubs because the 6th was thought to be too close to the wind leading edge and may damage it.

 

Merlins 21, 23 & 25 used in the FB.VI were single stage, hence 5 stubs. 

Oh, interesting. So would the props be slightly forward on the bomber compared to the fighter/bomber? (Also interesting that the earlier bomber variant actually had a better engine with two-stage supercharger. Seems backwards, though I can understand it having a greater need for high altitude performance vs. the mud mover variant.)

Thanks!

4 hours ago, SMH said:

Oh, interesting. So would the props be slightly forward on the bomber compared to the fighter/bomber? (Also interesting that the earlier bomber variant actually had a better engine with two-stage supercharger. Seems backwards, though I can understand it having a greater need for high altitude performance vs. the mud mover variant.)

Thanks!

Yes, the props are slightly forwards relative to the fuselage, this is easier to notice when observing directly from above.

A two-stage charger is not necessarily better than a single stage, as long as the single stage is able to maintain the required boost. The fighters and fighter bombers did not operate at 30k, so they did not need it - especially the FB.VI that rarely got over 10k. The PR and bombers did fly high. Later NF models like the NF.30 also used 2-stage Merlins.

On 8/18/2021 at 1:38 PM, Bozon said:

The two-stage chargers Merlins were installed a little more forward of the wing than the single stage Merlins. As a result, there was room for a 6th exhaust stub. The variants with a single stage Merlin had 5 stubs because the 6th was thought to be too close to the wind leading edge and may damage it.

 

Merlins 21, 23 & 25 used in the FB.VI were single stage, hence 5 stubs. 

That seems to confirm my preferred theory. I'm sure it can get pretty hot, but the "wing protection" idea seems a bit ludicrous, with the other pipes just centimetres away.

On 8/18/2021 at 9:30 AM, SMH said:

Oddly the earlier Mosquito bomber variant seems to have 6 individual stacks per side. They're often covered by a flame dampener too as they were night bombers.
 

 

 

I've read that those exhaust dampers were a problem for the engine performance, on the early models. I'll try to find a reference on that.

EDIT: it's in a book, "De Havilland Mosquito (Crowood Aviation Series)" by Martin Bowman, The Crowood Press, 2005. See for example here: https://military.wikia.org/wiki/De_Havilland_Mosquito (search for "flame dampers")

13 hours ago, Redglyph said:

I've read that those exhaust dampers were a problem for the engine performance, on the early models. I'll try to find a reference on that.

 

EDIT: it's in a book, "De Havilland Mosquito (Crowood Aviation Series)" by Martin Bowman, The Crowood Press, 2005. See for example here: https://military.wikia.org/wiki/De_Havilland_Mosquito (search for "flame dampers")

 

I would imagine some of that was the drag they caused as well. I know the FB variant was a bit slower than the bomber due to the flat windscreen vs. the split one on the bomber.

I'd think the night fighters would have all had them. No?

The exhaust design can provide additional thrust as well, quite a lot of thrust.

On 8/22/2021 at 7:42 AM, SMH said:

I would imagine some of that was the drag they caused as well. I know the FB variant was a bit slower than the bomber due to the flat windscreen vs. the split one on the bomber.

I'd think the night fighters would have all had them. No?

It could be additional drag.

They reduced the problem with "multiple ejector and open-ended exhaust stubs". So was there a compression issue?

Yes, I bet they'd rather have them at night, no matter what 

Saw some multiplayer testing screenshots, and three of the birds had the same tail codes (EG-H). Will we not be getting dynamic side numbers in the Mossie?

2 hours ago, Nealius said:

Saw some multiplayer testing screenshots, and three of the birds had the same tail codes (EG-H). Will we not be getting dynamic side numbers in the Mossie?

 

Could you post a link to these, thanks 

Ohhhhh this looks so good… 

Not long now Bozon!   

It will be released in 2 weeks middle of a house move for sure, 

Stunning screen shots. The detail is incredible! Notice how every aircraft has a navigator on board now. Anyone confirm what map that is?

Last time I was this wanting of a module release was the Spitfire IX way back... I can't remember when now!

Definitely the Channel. You can see Chain Home in the background.

God that coastal defense gray scheme is sexy. 

Maybe it was asked before, but will it have WHEEL CHOCKS? Almost all modern planes have chocks, but props do not, and not all of them have parking brakes, and all we can do is hold the W button for minutes until the engine warms up.

^ I doubt it will. However, IF the brake lever and its parking latch are implemented the same way as in DCS Spit, you will be able to engage the parking brake in a similar fashion (ie. putting the mouse cursor on the lever and rolling the scroll wheel).

On 8/27/2021 at 11:35 AM, WarbossPetross said:

Maybe it was asked before, but will it have WHEEL CHOCKS? Almost all modern planes have chocks, but props do not, and not all of them have parking brakes, and all we can do is hold the W button for minutes until the engine warms up.

its a bug for sure and a serious mistake to the real procedures for aircrafts from the IIWW, till now only jets has this (where we have parking brake mostly!) … LOL. I hope it will be solved for Mossie from beginning and looks like it will be here! However Mossie has working parking brake also.

1 hour ago, YoYo said:

its a bug for sure and a serious mistake to the real procedures for aircrafts from the IIWW, till now only jets has this (where we have parking brake mostly!) … LOL. I hope it will be solved for Mossie from beginning and looks like it will be here! However Mossie has working parking brake also.

 

 

Thanks for the screenshot- I can now read it clearly. What the heck is F5 on the list “Change cabin equipment”?

Sounds like redecoration of the cabin - a new floor mattress and a Moose head above the fireplace maybe?

Edit:

After careful consideration, I kindly ask ED to allow fuzzy dice hanging from the ceiling, leopard skin cover for the seats, and a plastic Jesus on the dashboard next to the gunsight.

2 minutes ago, Bozon said:

Thanks for the screenshot- I can now read it clearly. What the heck is F5 on the list “Change cabin equipment”?

Sounds like redecoration of the cabin - a new floor mattress and a Moose head above the fireplace maybe?

Fluffy Dice and a novelty gear knob.

9 minutes ago, Bozon said:

Edit:

After careful consideration, I kindly ask ED to allow fuzzy dice hanging from the ceiling, leopard skin cover for the seats, and a plastic Jesus on the dashboard next to the gunsight.

 

Like in SW: Squadron? 

Gee??

13 minutes ago, YoYo said:

 

Like in SW: Squadron? 

 

No no no, it needs to be over-the-top, more like this:

but with more big gold $ symbols and a giant boom box.