BF109G-6 flap question

[CATCplSlade]

Quick question: I have previously been building my aircraft in-flight to hang from my ceiling due to lack of shelf space, but that is coming to an end once I finish the new display cabinets in my office. So, how should the trailing edges look for one of these birds on the ground? I have looked online but there seems to be no definitive look. Is it up to how I want it to look? Period photos mostly indicate everything is up in the neutral position while most museum shots (and it seems most kit builds) have it all hanging loose - should I shoot for the middle ground? What gives?

 

Okay, so not A question.

Edited June 7, 2016 by CATCplSlade

[hworth18]

Many pics I have seen, the ailerons are close to neutral, the secondary flaps in a little lower position while the radiator flaps are down fully. But it's just about any way you want to pose them.

 

Edited June 6, 2016 by hworth18

[LSP_Ron]

IIRC, the rad flaps would always be down when on the ground as procedure or the engine would overheat very quickly if they forgot to drop them at start up.  I am sure others here will know for sure.  Kinda the opposite of Spitfire flaps which were raised immediately so they wouldn't block the radiator airflow.

 

Ron

[CATCplSlade]

Thanks for the responses. From outboard inward I did level-slight droop-full down as most seem to do them. I'll have to assume the gust lock is in there as I fixed the elevators relatively level before I read your post, Jennings. One was much looser than the other and did not want to hang right.

[LSP_Ron]

Makes sense

[CATCplSlade]

I'm not sure what kind of gust lock the 109 had.

 

It had the one Revell forgot to include; so I made one out of thin air.

 

Or sumthin' like dat.

[Darren Howie]

There are a lot of aircraft that use the worlds simplist gust lock ie the seatbelt.

On radiators variable positions are very possible.

In summer for ground ops yep open would be normal.

In winter closed to assist in engine/oil warming would be likely yet oust sortie open or closed depending on shock cooling is a possibility.

In short no single position is right.

Rules and aeroplanes generally don't go hand in hand particularly in bad weather and combat...

[Radub]

Making statements like "flaps on the (insert name of other plane here) were always (insert position of flap here)" while talking about the Bf 109 is futile. The flap+radiator arrangement on the Bf 109 was unique, very complex and bears no similarity to anything else. 

The coolant radiator had two flaps. The top radiator flap was controlled by a hydraulic piston linked to a thermostat, which moved it depending on the temperature of the coolant. The bottom radiator flap was secured with a pin to the landing flap. So, whatever position the landing flap was, so was the lower radiator flap. The landing flap was controlled by a large wheel on the left side of the pilot seat. The pilot adjusted it by turning that wheel as needed for the landing speed. After landing, if the pilot or ground crew did not bother to turn that wheel, the flap stayed in whatever position. 

Here is an explanation: http://109lair.hobbyvista.com/techref/systems/cooling/f_flaps.htm 

So, you can set your flaps/radiator flaps whichever way you want while keeping in mind that the lower radiator flaps MUST be at the same angle as the landing flap. 

Radu 

Edited June 7, 2016 by Radub

[Warbird]

Hi,

 

I don't think that the lower radiator flaps must be at the same angle as the landing flap.

 

Actually the only rule I could observed is that the landing flaps trailing edge must be in the middle of the space between the bottom and lower radiator flaps.

 

Btw, for 109 lovers here you can find almost all known 109 photos:

 

https://www.flickr.com/photos/28092068@N03/albums

 

[Radub]

OK, maybe I need to be more clear. I had the chance to see the landing flap and cooling flap move at the same time in Duxford. I also have plenty of books on the subject. 

In my post above, I also posted a link to an explanation of how flaps work. In the drawing below, taken from that link, there is a blue complex "Gator flap" scissor device. In the middle you can see a "circle". That "circle" is the place where it links to a pin on the side of the landing flap. When the landing flap moves, that whole "blue" assembly moves also. But when the green link moves, the coolant flaps open like a "butterfly". That is how you end up with the top coolant flap at a different angle from the bottom coolant flap. This operation is carried out by a hydraulic ram, controlled by an thermostat. So, for that reason, the two coolant flaps move together with the landing flaps but they can also move independently from the landing flaps. The top and bottom radiator flaps open to various degrees from each other, but there is a distinct correlation between the landing flaps and the radiator flaps. For that reason, it is impossible for the landing flaps to be down and the coolant flaps to be up - they move together. Yes, in some circumstances, when the coolant in the radiator is boiling hot, the coolant flaps may be opened fully by the thermostat/hydraulic ram beyond the angle of the landing flap, so you may end up with situations where the angles do not match precisely. Make no mistake, they are linked, but because the thermostatically controlled radiator flaps are linked to manually controlled landing flaps, you can get one million combinations of angles. Pick one, and it is right. Yet, more often than not, when the landing flaps are down, so are the radiator flaps. 

 

 

Also, have a look at this video. You can see them moving together. 

https://www.youtube.com/watch?v=qcMjhihuuX8

 

HTH 

Radu 

Edited June 7, 2016 by Radub

[Radub]

Radu - I don't see anywhere on your web site to purchase your 109 scale drawings.   Do you have them available?

The A3 printer (large format) that I used to print the drawings is no longer functional. You can find them in Brett Green's book on how to build the Revell Bf 109 G. 

HTH 

Radu 

[CATCplSlade]

Well, I committed to what I've done on this one, but I have an "E" and "F" to build later that I will apply this new knowledge to.

 

Thanks to all.

[LSP_K2]

Yep, the inboard flap was part and parcel of the radiator system on the 109.  It was possible for the upper portion to be raised and the lower portion (the actual aerodynamic flap surface) to be lowered.  

 

And don't forget that unless there was a gust lock installed (or the lap belt was wrapped around the stick), the elevators should be drooped on a parked 109.  In the photo above, I'd lay good money the lap belt was around the stick, pulling it all the way aft.  That way if you get a good gust of wind, it wants to force the tail down and keep the airplane on the ground.

 

When I see the term drooped, I think of the word lowered. You actually mean fully raised, correct?