Question re engine louvres (?)

[Guest]

Hi - found this image of one of my grandfather's planes: http://www.asisbiz.com/il2/Blenheim/RAF-211Sqn-UQ/pages/COD-asisbiz-MkI-RAF-211Sqn-UQ-L6670-Greece-April-1941-V03.html

It's CGI and all, but seems pretty faithful (there are questions about the colour of the code letters that you needn't bore yourselves with!). My question is about the louvres (is that the correct term?) around the engine which are depicted as being open: would this be the case in flight? My understanding was that they'd be open on the ground to provide extra cooling while stationary, but closed in flight. Am I right or have I got the wrong end of the stick?

Ta!

[stona]

Those are correctly called cowl flaps. I don't know how they were controlled on a Blenheim (I don't think that they were automatic) but in most normal flight regimes they would not be fully opened like that. There was a significant drag penalty incurred to achieve the extra cooling capacity.

They might be partially open during a hard climb for example. I don't have the pilots' notes for the Blenheim so I can't be more specific about settings.

Cheers

Steve

[Dave W]

Have you managed to get hold of a 1/48 Blenheim kit yet Alasdair?

[eddiesolo]

I did find this: http://www.theairtacticalassaultgroup.com/wiki/doku.php?id=blenhiem_mkiv

Si

[Guest]

Very interesting aircraft Alasdair.

Looked at these below and the detail does not seem to match the photo you have posted. The posted photo seems remarkable for that time. Is it a very good model or a renovated real thing. Can not see a photo of that quality for 1941 or an aircraft of that quality finish. !!!!!

In the movie clip there was certainly no movement on the apparent ? engine cowl flaps. There is an air inlet at the back of the cowl ie a gap between the cowl and the futher back part of the casing. If that makes sense. Do not know if you can make head or tail of that Steve. Being a radial as the Beaufighter I can not remember opening cowls for the Beau.

http://en.wikipedia.org/wiki/Bristol_Blenheim#mediaviewer/File:Bristol_Blenheims_62_Squadron_Singapore_Feb_1 941.jpg

https://www.google.com/search?q=blenheim+aircraft&client=firefox&hs=E6w&r ls=com.yahoo:en-GBfficial&channel=sb&tbm=isch&imgil=JUl8dJDL158faM%2 53A%253Bhttps%253A%252F%252Fencrypted-tbn0.gstatic.com%252Fimages%253Fq%253Dtbn%253AANd9 GcQ5SvceWb4Q8zPoeOdOgpq84p4y4EGcG9vH1xO0hIkKRZdnyj syng%253B800%253B600%253B3PsI-K5IJZFe2M%253Bhttp%25253A%25252F%25252Fww2today.co m%25252Fblenheim-pilot-wins-empire-gallantry-medal&source=iu&usg=__1xJqRwMrj7odgtul2p9yADxMtQs% 3D&sa=X&ei=7VfZU4COEsbb7Abs2oDoCA&ved=0CDEQ9QEwAg& biw=1920&bih=827#facrc=_&imgdii=_&imgrc=JUl8dJDL15 8faM%253A%3B3PsI-K5IJZFe2M%3Bhttp%253A%252F%252Fww2today.com%252Fwp-content%252Fuploads%252F2010%252F03%252FBristol_Bl enheim.jpg%3Bhttp%253A%252F%252Fww2today.com%252Fb lenheim-pilot-wins-empire-gallantry-medal%3B800%3B600

https://www.google.com/search?q=blenheim+aircraft&client=firefox&hs=E6w&r ls=com.yahoo:en-GBfficial&channel=sb&tbm=isch&imgil=JUl8dJDL158faM%2 53A%253Bhttps%253A%252F%252Fencrypted-tbn0.gstatic.com%252Fimages%253Fq%253Dtbn%253AANd9 GcQ5SvceWb4Q8zPoeOdOgpq84p4y4EGcG9vH1xO0hIkKRZdnyj syng%253B800%253B600%253B3PsI-K5IJZFe2M%253Bhttp%25253A%25252F%25252Fww2today.co m%25252Fblenheim-pilot-wins-empire-gallantry-medal&source=iu&usg=__1xJqRwMrj7odgtul2p9yADxMtQs% 3D&sa=X&ei=7VfZU4COEsbb7Abs2oDoCA&ved=0CDEQ9QEwAg& biw=1920&bih=827#facrc=_&imgdii=_&imgrc=c_PZPe2jcG Y2CM%253A%3BckafqUbOMbObkM%3Bhttp%253A%252F%252Fcd n-www.airliners.net%252Faviation-photos%252Fphotos%252F9%252F8%252F5%252F2013589.jp g%3Bhttp%253A%252F%252Fwww.airliners.net%252Fphoto %252FUK---Air%252FBristol-142M-Blenheim%252F2013589%252FL%252F%2526sid%253D82253a db9ff950acd518241a4e4388f5%3B1024%3B719

Laurie

[flyjoe180]

Cowl flaps are as Steve described. They are a cooling device; opened on the ground and during high power/low airspeed regimes, closed in the cruise and opened again prior to landing. They are usually closed after shut down to preserve heat and prevent foreign object ingress. They would be closed for that flying display Laurie, plenty of airspeed, but they are open at the start and taxi. I doubt the Blenheim's cowl flaps were automatic. Bristol designed it's own cowl flaps (AKA gills back in the day) for it's Bristol radial engines. The Beaufighter, Laurie, had cowl flaps also.

[Guest]

Thanks for your responses everyone, think I understand this all now.

Dave - No luck getting hold of a 1/48 Blenheim Mk I - a few have come on the market, but prices seem to have gone up from approx £50 to around £70 or even higher now... just way out of my budget.

I've had to put the modelling to one side for the past four or five months (hence my absence from the forum too!) as work just got incredibly hectic. Hoping to have some spare time soon, so will be picking up the paints & glues any time now and cracking on... Looks like the new Airfix 1/72 scale Blenheim Mk I is a pretty good kit, so will pick one of those up as soon as I can.

Laurie, thanks for the vid, hadn't seen that one. I believe this plane crashed at Duxford in 2003, it's now being restored (again!) but this time as a Mk I version, by the Aircraft Restoration Company based there - more info on their page at http://www.arc-duxford.co.uk/restorations/blenheim/. Actually, the image I posted was computer-generated (!!), I think for a flight sim programme but not sure which... pretty impressive image quality I thought, computers have come a long way since I first tried a flight sim programme:

[ATTACH]86431.IPB[/ATTACH]


:-)

[Guest]

Thanks Alasdair. The write up by the ARC is very interesting. Love to see this in flight.

As you mention Airfix do a 1/72. It is a remarkable aircraft for 1934. Think I will add this to my list.

1/48 sounds good but not at that price.

Laurie

[tr1ckey66]

Hi Alistair

I do hope you can get hold of a suitable kit and model your grandfather's aircraft. The Blenheim is a fascinating subject and will look very cool. That coupled with your own family connection should make it a really enjoyable build.

Cheers

Paul

[Guest]

Thanks Paul - this is the plane I want to do:

[ATTACH]86451.IPB[/ATTACH]


It's airframe L6670 wearing the 211 Sqn ID letters UQ-R (actually the R was never painted on for some reason - other planes in the sqn did have their full ident painted on), pictured here landing at RAF Menidi, just north of Athens in 1940 (ref: www.211squadron.org, the 211 sqn memorial website). Corgi actually did a diecast of this a few years ago (http://www.flyingmule.com/products/CG-AA38404), but I couldn't afford it!

Fortunately, there are decals for this plane in both 1:48 and 1:72 (http://www.hannants.co.uk/product/X72202), so should be easy enough to get together.

As soon as I find some time...!