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Dunkirk Spitfire

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cgwilson View Drop Down
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    Posted: 30 Mar 2018 at 9:26am
I purchased this yesterday and have to say I am disappointed in it.

The modelling looks funny, I think the front end ,forward of the windscreen is too round on the top. I also would say that the handling, especially the roll rate is too slow. I have several versions of the Spit, the A2A and Real Air ones in particular, and comparing them it is obviously wrong. 
I have worked around them for years in real life and flown in them so I think I know what wrong and what's not
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Voice of Reason Quote  Post ReplyReply Direct Link To This Post Posted: 30 Mar 2018 at 9:48am
Originally posted by cgwilson cgwilson wrote:

I purchased this yesterday and have to say I am disappointed in it.

The modelling looks funny, I think the front end ,forward of the windscreen is too round on the top. I also would say that the handling, especially the roll rate is too slow. I have several versions of the Spit, the A2A and Real Air ones in particular, and comparing them it is obviously wrong. 
I have worked around them for years in real life and flown in them so I think I know what wrong and what's not

If you've purchased it and don't approve and won't use it going forward get in touch for a refund via the support team.  Or if you believe you have some feedback that might help with improving the model then please pass that on to the support team too.

Many other people have purchased this and are very happy with it so it's a little surprising to hear of your disappointment but each to their own and of course you're entitled to your opinion.
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Delta558 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Delta558 Quote  Post ReplyReply Direct Link To This Post Posted: 30 Mar 2018 at 6:23pm
Caveat: I do not have this product, nor did I work on it. Therefore, I have no idea how it flies in the sim.

Originally posted by cgwilson cgwilson wrote:

I also would say that the handling, especially the roll rate is too slow. I have several versions of the Spit, the A2A and Real Air ones in particular, and comparing them it is obviously wrong. 
I have worked around them for years in real life and flown in them so I think I know what wrong and what's not


I believe that Aeroplane Heaven have modelled the very early Mk1 Spitfire, with fabric covered ailerons. Both the A2A and RealAir Spitfires have the slightly later metal-covered surfaces (see quote below for relevance) and the RealAir is a completely different airframe - MkIX and XIV - with numerous improvements so it is a very unrealistic comparison and can effectively be discounted.

From a very quick internet search for "Spitfire fabric ailerons":

All of the main flight controls were originally metal structures with fabric covering.Designers and pilots felt that having ailerons which were too heavy to move at high speed would avoid possible aileron reversal, stopping pilots throwing the aircraft around and pulling the wings off. It was also felt that air combat would take place at relatively low speed and that high-speed manoeuvring would be physically impossible. During the Battle of Britain, pilots found the ailerons of the Spitfire were far too heavy at high speeds, severely restricting lateral manoeuvres such as rolls and high-speed turns, which were still a feature of air-to-air combat. Flight tests showed the fabric covering of the ailerons "ballooned" at high speeds, adversely affecting the aerodynamics. Replacing the fabric covering with light alloy dramatically improved the ailerons at high speed.

There are many references to this, and it may well explain why the aircraft handles 'slowly' in your opinion when compared to the A2A product. At the end of the day, you have two very different Mk1 Spits and unless you are one of the incredibly lucky few people who have actually been able to  experience both variants in real life of recent years then I don't think any of us are in a position to say that either is 'perfect' while the other is 'wrong'.

Cheers,
Paul.
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cgwilson View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote cgwilson Quote  Post ReplyReply Direct Link To This Post Posted: 30 Mar 2018 at 7:40pm
These Spitfire roll rate data were taken from THE DEVELOPMENT OF THE SPITFIRE AND SEAFIRE - 706th lecture delivered before the Royal Aeronautical Society (19 Dec 1946) by J. Smith (chief designer for Supermarine during the war).

Herewith follows the roll rate graph values, as closely as I can approximate them:

All data are give for "full aileron or 50 lb stick force" - I suppose whichever limit was achieved first.

All air speeds are given as "equivalent air speed". Not sure what is meant by this term; I'm guessing that it means indicated airspeed.

Spitfire V / fabric covered frise ailerons:
90 deg/sec @ 170 mph (lowest speed graphed)
75 deg/sec @ 200 mph
55 deg/sec @ 250 mph
40 deg/sec @ 300 mph
27 deg/sec @ 350 mph
20 deg/sec @ 380 mph (end of graphed values)

Spitfire Mk V / metal covered frise ailerons
85 deg/sec @ 150 mph
105 deg/sec @ 200 mph
90 deg/sec @ 250 mph
75 deg/sec @ 300 mph
60 deg/sec @ 350 mph
40 deg/sec @ 400 mph

Spitfire Mk V / plain ailerons with tabs
65 deg/sec @ 180 mph
75 deg/sec @ 200 mph
95 deg/sec @ 250 mph
118 deg/sec @ 300 mph
90 deg/sec @ 350 mph
70 deg/sec @ 400 mph

The explanatory text which accompanied the graphs follows:

QUOTE -
Careful analysis over a long period of time on various marks of Spitfire had revealed fairly wide variations in aileron section and in the position of the ailerons relative to the wings. These differences resulted in inconsistent aileron characteristics, and it was felt that ailerons of a type which would be simple to manufacture and which would be less sensitive to manufacturing tolerances were necessary.

Quantitative data obtained from flight trials on a Spitfire Mark V with plain ailerons fitted with a balance tab had previously indicated that aileron properties comparable with those of a metal-covered Frise type could be achieved, with a reduction in drag due to the elimination of the gap. Ailerons of this type with area increased to 6 per cent of the total wing area, as against 5 per cent on earlier marks, were fitted to the stiffer Mark 21 wing and gave a high rate of roll with reasonable stick forces at high speeds.

- UNQUOTE

Smith then goes on to show a graph of stick efforts required to "apply 1/4 aileron at various speeds.

Spitfire V / fabric covered frise ailerons
8 lbs @ 200 mph
16 lbs @ 250 mph
27 lbs @ 300 mph
43 lbs @ 350 mph
57 lbs @ 375 mph (end of graphed values)

Spitfire V / plain ailerons with tabs
7 lbs @ 200 mph
9 lbs @ 250 mph
13 lbs @ 300 mph
18 lbs @ 350 mph
24 lbs @ 400 mph

Spitfire V / metal covered frise ailerons
4 lbs @ 200 mph
5 lbs @ 250 mph
7 lbs @ 300 mph
9 lbs @ 350 mph
12 lbs @ 400 mph

Smith elsewhere mentions in passing some roll rate values for other Spitfire Marks, to wit -

Spitfire I - 14 deg/sec @ 400 mph
Seafire 47 - 68 deg/sec @ 400 mph


Hope this helps.


So you can see that with fabric elevators (early build Mk Vs) the peak roll is a mere 90 deg/sec at 170mph. While with metal covered alierons that increases to 105 deg/ sec at 200 mph and plain alierons with tabs it goes all the way up to 118 deg/ sec at 300mph.
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Delta558 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Delta558 Quote  Post ReplyReply Direct Link To This Post Posted: 30 Mar 2018 at 8:27pm
A fascinating section of data - as i mentioned, I don't have the aircraft but seeing the variation at higher speeds for the differing aileron types is definitely interesting.

Of note is the Mk1 sneaking in at the end there with a pitiful 14deg/sec at speed and when you compare the Mk5 fabric v metal and see the considerable difference in roll rates at all but the lowest measured speeds (1.5 to 2 times with metal), I'd say that probably accounts for at least some of what you are seeing in the AH model.

Thanks for sharing that, it's the sort of info developers can always make use of.
Paul.
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