RAF Chipmunks
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I42 ...
A bit more info for you as promised. I hope it's of interest. Please note that the diagram/data below is for a Mk21 Chipmunk NOT a UK Mil TMk10. The data is also 'representative' and NOT specific to a particular aircraft. The diagram also shows a Narrow Chord Rudder and the absence of Spinning Strakes, both these MOD's will impact CoG Calcs. RAF Chipmunk equipment, e.g. Radios, were significantly different (heavier).
The CoG position is determined with the aircraft in the 'Rigging Position' (Fuselage Datum Line, Horizontal) as determined by physically levelling the aircraft with respect to the Forward Levelling Peg and the Datum Point, and is found in the usual way of taking moments about the Datum Point.
The Datum Point (Port Side) is an arbitrary position some 36 inches Aft of the Forward Levelling Peg ... both these positions are on the FDL).
In this example the CoG Limit of Travel is ...
Forward Limit (-) 6.80 inches Forward of CoG Datum Point
Aft Limit (-) 0.77 inches Forward of CoG Datum Point
MAUW 2,100 lb
Max Luggage Locker Limit 40 lb
Measured parallel to the Fuselage Horizontal Datum Line. The vertical position of the CoG was ignored provided published loading limits were respected.
For reference the RAF Pilots Notes (AP 4308 3rd Edition) quoted the following limits ...
Forward Limit (-) 6.48 inches Forward of CoG Datum Point
Aft Limit (+) 0.257 inches Aft of CoG Datum Point
MAUW 2,100 lb
Max Luggage Locker Limit 40 lb
A bit more info for you as promised. I hope it's of interest. Please note that the diagram/data below is for a Mk21 Chipmunk NOT a UK Mil TMk10. The data is also 'representative' and NOT specific to a particular aircraft. The diagram also shows a Narrow Chord Rudder and the absence of Spinning Strakes, both these MOD's will impact CoG Calcs. RAF Chipmunk equipment, e.g. Radios, were significantly different (heavier).
The CoG position is determined with the aircraft in the 'Rigging Position' (Fuselage Datum Line, Horizontal) as determined by physically levelling the aircraft with respect to the Forward Levelling Peg and the Datum Point, and is found in the usual way of taking moments about the Datum Point.
The Datum Point (Port Side) is an arbitrary position some 36 inches Aft of the Forward Levelling Peg ... both these positions are on the FDL).
In this example the CoG Limit of Travel is ...
Forward Limit (-) 6.80 inches Forward of CoG Datum Point
Aft Limit (-) 0.77 inches Forward of CoG Datum Point
MAUW 2,100 lb
Max Luggage Locker Limit 40 lb
Measured parallel to the Fuselage Horizontal Datum Line. The vertical position of the CoG was ignored provided published loading limits were respected.
For reference the RAF Pilots Notes (AP 4308 3rd Edition) quoted the following limits ...
Forward Limit (-) 6.48 inches Forward of CoG Datum Point
Aft Limit (+) 0.257 inches Aft of CoG Datum Point
MAUW 2,100 lb
Max Luggage Locker Limit 40 lb
Last edited by CoffmanStarter; 15th Jun 2015 at 18:16.
Coff #278,
I seem to recall both of those datum points being used to determine the longitudinal datum when positioning the aircraft in "rigging position" during servicing. The Lateral position used, I recall, was across the canopy rails. My fondest memory of the use of the canopy rails was a combined OUAS/LUAS and 6AEF beer call when all of our Chipmunks held a Firkin of Hook Norton Bitter across the rear cockpit rails. Possibly the last time that I enjoyed a pint within 2 feet of an Aircraft. Honest
Smudge
I seem to recall both of those datum points being used to determine the longitudinal datum when positioning the aircraft in "rigging position" during servicing. The Lateral position used, I recall, was across the canopy rails. My fondest memory of the use of the canopy rails was a combined OUAS/LUAS and 6AEF beer call when all of our Chipmunks held a Firkin of Hook Norton Bitter across the rear cockpit rails. Possibly the last time that I enjoyed a pint within 2 feet of an Aircraft. Honest
Smudge
a Firkin of Hook Norton Bitter across the rear cockpit rails.
Got a picture?
CS,
Thanks for the picture. It is interesting that the side view and the table show arms forward of the datum as negative and yet the chart shows the arm as positive!
I've recently been teaching W&B in a glider ground school and have found similar inconsistencies in glider handbooks. It's stuff like this that makes what should be a relatively straightforward topic, more complex and error prone than it needs to be.
However, as I've said before, in my time at UBAS, W&B was never mentioned, so it wasn't an issue!
Thanks for the picture. It is interesting that the side view and the table show arms forward of the datum as negative and yet the chart shows the arm as positive!
I've recently been teaching W&B in a glider ground school and have found similar inconsistencies in glider handbooks. It's stuff like this that makes what should be a relatively straightforward topic, more complex and error prone than it needs to be.
However, as I've said before, in my time at UBAS, W&B was never mentioned, so it wasn't an issue!
India 42:
Great photos, I've never seen the second one.
I'm not sure I agree here. But notice the spinner marked in the university colours and the canopy frame. While most Chipmunks in the overall LAG scheme had grey framing, a significant number had the frames in white.
SOMEWHERE here I've got a photo of University of Wales Chipmunks with similar decoration to WD353, only this time the stripe is green/white with the Welsh flag at the forward end.
I wonder if these flamboyant UAS markings caused sometime in authority to take fright? The "standardized" UAS marking - a shield with a device unique to that university, flanked by bars in the university colours carried below the rear cockpit - appeared shortly after these photos were taken.
The significance of the WK507 photo is that this is only one of two Chipmunks ever photographed in the Red/White/Light Grey scheme and sporting UAS markings.
I'll post later about Chipmunk W & B - but I don't think either the strakes or the enlarged rudder weighed very much...
Great photos, I've never seen the second one.
A nice photo, but I have to say, I prefer this one:
SOMEWHERE here I've got a photo of University of Wales Chipmunks with similar decoration to WD353, only this time the stripe is green/white with the Welsh flag at the forward end.
I wonder if these flamboyant UAS markings caused sometime in authority to take fright? The "standardized" UAS marking - a shield with a device unique to that university, flanked by bars in the university colours carried below the rear cockpit - appeared shortly after these photos were taken.
The significance of the WK507 photo is that this is only one of two Chipmunks ever photographed in the Red/White/Light Grey scheme and sporting UAS markings.
I'll post later about Chipmunk W & B - but I don't think either the strakes or the enlarged rudder weighed very much...
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I42 ...
I agree with your point on the Fuel Weight Graph Y Axis above
Smudge ...
You've got to find that pic old chap ... could it possibly be in that Nav Bag that Mrs S still has to find
Dora-9 ...
Looking forward to more pics and W&B info ... have you still got the 700 entries for your airframe ?
Best ...
Coff.
I agree with your point on the Fuel Weight Graph Y Axis above
Smudge ...
You've got to find that pic old chap ... could it possibly be in that Nav Bag that Mrs S still has to find
Dora-9 ...
Looking forward to more pics and W&B info ... have you still got the 700 entries for your airframe ?
Best ...
Coff.
Dora-9,
The first one I found on the web. It was taken at Shawbury in 1968. Judging by the barrier and the crowd in the background, it was probably the day of the de Havilland Trophy intra-UAS aerobatics and spot-landing competition. The UBAS entrant in the competition was Jock Lowe who went on to bigger and better things - he became a Concorde captain.
I have some similar prints taken at the same time, but they are buried in storage.
The second one hasn't appeared on the Internet before. That is me at my last Summer Camp at Marham in 1969. I vividly remember one incident from that camp. I was enjoying myself on a solo "L/L Navex", zipping across the Fens at 250' (or so
), when Marham called up "I42, what's your altitude?" I was thinking "Whoops, busted" but dutifully replied "250' AGL". "Roger, we've got the Reds in transit at 2000' "
I swivelled my head everywhere, but never did see them. It's hard to believe now but we actually got paid to have a lot of fun and there was absolutely no pressure to join the RAF.
Concerning your thoughts on the colour schemes, you may be right. In my three years, we had three different colour-schemes, each one becoming more flamboyant and more UBAS oriented. The first year, we had silver Chipmunks with dayglo panels, the second year, the grey/dayglo scheme had been introduced and the third year, they came back from having UHF installed, now sporting the white canopy-frames.
The first one I found on the web. It was taken at Shawbury in 1968. Judging by the barrier and the crowd in the background, it was probably the day of the de Havilland Trophy intra-UAS aerobatics and spot-landing competition. The UBAS entrant in the competition was Jock Lowe who went on to bigger and better things - he became a Concorde captain.
I have some similar prints taken at the same time, but they are buried in storage.
The second one hasn't appeared on the Internet before. That is me at my last Summer Camp at Marham in 1969. I vividly remember one incident from that camp. I was enjoying myself on a solo "L/L Navex", zipping across the Fens at 250' (or so
), when Marham called up "I42, what's your altitude?" I was thinking "Whoops, busted" but dutifully replied "250' AGL". "Roger, we've got the Reds in transit at 2000' " I swivelled my head everywhere, but never did see them. It's hard to believe now but we actually got paid to have a lot of fun and there was absolutely no pressure to join the RAF.
Concerning your thoughts on the colour schemes, you may be right. In my three years, we had three different colour-schemes, each one becoming more flamboyant and more UBAS oriented. The first year, we had silver Chipmunks with dayglo panels, the second year, the grey/dayglo scheme had been introduced and the third year, they came back from having UHF installed, now sporting the white canopy-frames.
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Hi I do know that the Naval Chipmunks and I believe the Army ones were never wired hot,this info came from my father who was an instructor at Roborough with the BRNC flight
apologies for commenting when not qualified personally to do so
Gordon
apologies for commenting when not qualified personally to do so
Gordon
More W&B information
I looked at the Canadian Chipmunk documents that I have, for W&B information.
The 1950 civil DHC-1 manual specifies the datum as 42" aft of the firewall and the rigging position is set by levelling the canopy rails. There are no "Datum Points" or "Levelling Pegs". The CG range is -8.91" to -0.72", gross weight 1930 lb.
Nothing to do with W&B, but in the same manual, there is this tantalizing three-view:
The 1958 RCAF Pilot's Operating Instructions for the DHC-1B (EO 05-10B-1) specifies a gross weight of 2000 lb, but refers to another document (EO 05-10B-8, which I don't have) for W&B details.
Again, although not about W&B, these cartoons are worth capturing. Much more fun than the RAF's T10 documents:
The 1957 DHC-1B-2 Flight Manual is a civilianized, expanded version of an RCAF manual. The gross weight is 2000 lb and the CG limits are the same as the 1950 manual.
There are also a couple of new cartoons:
Finally, I have a copy of the 1968 CAF manual, but I have just noticed the W&B page is missing! There must have been a "sense-of humour loss" at DND headquarters, because the cartoons are gone, but there is a new, interesting chapter with Flight Test procedures.
The 1950 civil DHC-1 manual specifies the datum as 42" aft of the firewall and the rigging position is set by levelling the canopy rails. There are no "Datum Points" or "Levelling Pegs". The CG range is -8.91" to -0.72", gross weight 1930 lb.
Nothing to do with W&B, but in the same manual, there is this tantalizing three-view:
The 1958 RCAF Pilot's Operating Instructions for the DHC-1B (EO 05-10B-1) specifies a gross weight of 2000 lb, but refers to another document (EO 05-10B-8, which I don't have) for W&B details.
Again, although not about W&B, these cartoons are worth capturing. Much more fun than the RAF's T10 documents:
The 1957 DHC-1B-2 Flight Manual is a civilianized, expanded version of an RCAF manual. The gross weight is 2000 lb and the CG limits are the same as the 1950 manual.
There are also a couple of new cartoons:
Finally, I have a copy of the 1968 CAF manual, but I have just noticed the W&B page is missing! There must have been a "sense-of humour loss" at DND headquarters, because the cartoons are gone, but there is a new, interesting chapter with Flight Test procedures.
I do know that the Naval Chipmunks and I believe the Army ones were never wired hot
Welcome to the thread and thanks for your input. I was beginning to think I had misheard what was said on the video about carb heat and of course, I haven't been able to find the video again!
Wander00,
I don't think so. I'm sure there would be pictures "floating around" if it was. There's also a ski-equipped three-view in the same manual.
PS but I did come across this surprise while looking:
I don't think so. I'm sure there would be pictures "floating around" if it was. There's also a ski-equipped three-view in the same manual.
PS but I did come across this surprise while looking:
Last edited by India Four Two; 16th Jun 2015 at 10:12.
Coff, India 42,
I'm sorry to say I never did have a photograph of the Barrels on the canopy rails. It must have been a memorable do though, I seem to recall we "put away" 6 x 88 pint firkin (I believe the 88 pint jobby is a firkin) in around 2 hours. That would be the UAS staff instructors, that days 6 AEF pilots and around half the ground crew (in all a maximum of fifty people). Like all things that are great memories, I so often failed to record them with a camera.
Smudge
I'm sorry to say I never did have a photograph of the Barrels on the canopy rails. It must have been a memorable do though, I seem to recall we "put away" 6 x 88 pint firkin (I believe the 88 pint jobby is a firkin) in around 2 hours. That would be the UAS staff instructors, that days 6 AEF pilots and around half the ground crew (in all a maximum of fifty people). Like all things that are great memories, I so often failed to record them with a camera.
Smudge
Flying off floats is top of my bucket list
Do it. I have about 20 hours on floats. It combines all the fun of lightplane flying with the fun of "simply messing about in boats".
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21 years ago, a 9 AEF (Finningley) Chipmunk was the first aircraft I ever flew in.
Happy memories, of waddling out like a pregnant duck and minding my step onto the black pads on the fabric wing. That smell others have mentioned previously. I was amazed how something looking so old and fragile can be so aerobatic. I have memories of a Seaking pilot flying a AEF chipmunk at a Kinloss summer camp and he had eyes in back of his head ( he knew when I was looking at the artificial horizon, was there a mirror in the front ?).
Years later, I remember seeing a Chimpunk at Cranwell or Bicster Gliding Club used for aero-tows. However it had an unusual cowling as a different engine was fitted.
Just out of interest, what is the going rate for buying a Chipmunk and what are the running costs like? Is ownership comparable to other light aircraft like Cessna 152 or does it need more TLC ?
Happy memories, of waddling out like a pregnant duck and minding my step onto the black pads on the fabric wing. That smell others have mentioned previously. I was amazed how something looking so old and fragile can be so aerobatic. I have memories of a Seaking pilot flying a AEF chipmunk at a Kinloss summer camp and he had eyes in back of his head ( he knew when I was looking at the artificial horizon, was there a mirror in the front ?).
Years later, I remember seeing a Chimpunk at Cranwell or Bicster Gliding Club used for aero-tows. However it had an unusual cowling as a different engine was fitted.
Just out of interest, what is the going rate for buying a Chipmunk and what are the running costs like? Is ownership comparable to other light aircraft like Cessna 152 or does it need more TLC ?
Last edited by gr4techie; 16th Jun 2015 at 17:51.