RFI: Looking for flight information on the DeHavilland Mosquito

[imipak]

There are a LOT of papers at the National Archives, but it has been proving impossible for me to get down there and dig through for the information on the DeHavilland Mosquito for their wind tunnel test data and information on flight characteristics. The problem is that these papers aren't in standalone sections, I've asked the National Archives and they have said that everything on the DH98 is pretty much lumped together and they're not interested in trying to sort out which file is where.

Which is fair enough - this is a fairly niche interest.

However, for my own project, I'm going to need as much information as I can get from those papers. The Merlin 130 wind tunnel test data (which they did send) is absolutely fantastic stuff.

Does anyone know of anyone who has collected this information together?

(I'm fairly sure the Mosquito Project in the UK has, but they never responded to my emails, so I'm assuming they're either snowed under with work or are otherwise unable to reply. Which is, again, fair enough.)

This information is absolutely essential if I'm to understand the forces that are imposed on the airframe as a result of the design and the limitations of the specific airfoil they were using.

 

[imipak]

Ok, this is NOT an absolutely complete list of everything the National Archives currently has on the DeHavilland Mosquito there's a lot of modification files I didn't include and there may be sections I missed. Also, I'm relying on what's been entered into the online search engine, there may be other files not yet added. I also threw in a few files on the DeHavilland Hornet. I did not put in all of the modifications lists, for example. But everything else, along with a couple dozen kitchen sinks, is. Even if nobody know where I could get any of these, this would likely be a useful historical list of reports for anyone interested in the Mosquito.

AVIA 6/2431 (modification to reduce vibration and tail buffeting) - B.A. 1677
AVIA 6/9499 (brake flaps and reversed thrust airscrews on Mosquito aircraft) - AERO: WIND TUNNEL NOTES 538
AVIA 6/9513 (umbrella brake flaps on Mosquito aircraft: tests) - AERO: WIND TUNNEL NOTES 554
AVIA 6/10501 (Measurements of maximum lift coefficients on a Mosquito IV fast medium twin-engined fighter bomber) - TN Aero 1383
AVIA 6/10638 (Nacelles for twin-engined Hornet fighter: high speed wind tunnel tests) - TN Aero 1521
AVIA 6/10737 (Drop tanks of Hornet aircraft: wind tunnel tests) - TN Aero 1622
AVIA 6/13783 (Mosquito aircraft and Steiger slip wing project: performance comparisons) - PN Aero 45
AVIA 6/16050 (Examination of DTD 363A extrusion for Hornet wing spar) - report 69
AVIA 10/364 (Mosquito research) - AR200/231
AVIA 20/141 (Knife edge cutter installed in Mosquito aircraft outer wing: experiments) - KB/R/234/DA
AVIA 54/99 (Mosquito B Mk35: conversion to new bomber standard; major modification release) - 7/Aircraft/1355

DSIR 23/10887 (DH 98 Mosquito aircraft: model experiments on balance of elevators and rudder)- report 5050
DSIR 23/11659 (Mosquito aircraft propellor blades) - report 5822
DSIR 23/11989 (maximum lift of Mosquito aircraft: wind-tunnel measurements) - report 6152
DSIR 23/12110 (longitudinal stability part 1) - report 6273
DSIR 23/12180 (Mosquito propellor blades) - report 6343
DSIR 23/12310 (longitudinal stability) - report 6473
DSIR 23/12316 (Static longitudinal stability of Mosquito aircraft and effect of tail twist) - report 6479
DSIR 23/12658 (aircraft elevator: calculation of twist) - report 6821
DSIR 23/12659 (looks like part 2 of above) - report 6822
DSIR 23/12660 (aircraft elevator: torsional stiffness) - report 6823
DSIR 23/13831 (Mosquito aircraft fitted with metal covered elevators: longitudinal stability) - report 7994
DSIR 23/14139 (Twin engined Mosquito fighter bomber elevator: pressure exploration on elevator horn balance and hinge moment measurements in RAE 24 ft wind tunnel) - report 8302
DSIR 23/14140 (looks like part 2 of above) - report 8303
DSIR 23/14362 (high-speed wind tunnel tests) - report 8525
DSIR 23/14426 (Twin engined F12/43 Hornet aircraft with contra rotating propellers: wind tunnel tests) - report 8589
DSIR 23/14500 (Maximum lift coefficients on Mosquito XXV aircraft with incidence measurements) - report 8663
DSIR 23/15312 (Wind tunnel tests on de Havilland Hornet F12/43 twin engined fighter aircraft: take off and landing with ground represented) - report 9475
DSIR 23/16395 (related load tests on Mosquito wing) - ARC 10558

AIR 10/2812 (Mosquito FII modifications only) - AP No. 2019B
AIR 10/2816 (Mosquito T III and Modifications) - AP No. 2019C Vol II Part I
AIR 10/2824 (Mosquito B IV: Modification & amendment leaflets only) - AP No. 2019D Vol II Part I
AIR 10/2833 (Mosquito N.F.XII: leaflets and modification sheets only) - AP No. 2019G
AIR 10/2836 (Mosquito N.F.XIII: leaflets and modification sheets only) - AP No. 2019H
AIR 10/2849 (Mosquito FB MK.21: modification leaflets) - AP No. 2019P Vol II Part I
AIR 10/2850 (Mosquito NF MK XIX: modification leaflets) - AP No. 2019R Vol II Part I
AIR 10/2851 (Mosquito B.MK 25: modification leaflets) - AP No. 2019S Vol II Part I
AIR 10/2853 (Mosquito F.B. MK26: modification leaflets) - AP No. 2019T & U Vol II Part I
AIR 10/3426 (Mosquito B IX modifications & leaflets) - AP No. 2653A VOL II Part I
AIR 10/3437 (Mosquito PR MK VIII Modification leaflets) - AP No. 2653F VOL II Part I
AIR 10/4477 (Mosquito FB VI Modification and amendment leaflets only) - AP No. 2019E Vol 2 Part I
AIR 10/4777 (Mosquito B MK XVI: Modification leaflets and amendments) - AP No. 2653H
AIR 10/4842 (Mosquito N.F. MK.38: Modification and amendment leaflets) - AIR 10/4842
AIR 10/6266 (Mosquito aircraft: modification lists) - AP2653 ML
AIR 10/6268 (Mosquito B Mk 35 - elevator horn balance: leaflets and amendments) - AP2653N Vol 1
AIR 10/6278 (Mosquito TT Mk 35 aircraft: general orders and modifications) - AP2653S Vol 2
AIR 10/6288 (Mosquito PR Mk 35 aircraft: general orders and modifications) - AP2653T Vol 1
AIR 20/7190 (AIRCRAFT: Bombers (Code 5/3): Mosquito: modification policy. AIRCRAFT: Modifications, General (Code 5/20): Mosquito: policy) - ID/31/79 D of Wps/S (W Dev) 4048

 

[Simon Thomas]

I am not sure wind tunnel test reports will give a precise lift force number being put into the fuselage. e.g. at the maximum theoretical G, the wind tunnel number will not allow for the fact that on the real aeroplane the load of the engine at the long moment arm from the centre of torsion of the wing will twist the wing. This will change the AoA vs load.
What exactly are you looking for? I suspect that FEA and CFD will give better results than wind tunnel testing , although still not as good as testing a real airframe.

 

[imipak]

No, I agree. I would not expect the wind-tunnel reports to give a precise full-airframe lift/load number, especially not at the limiting load case. The real aircraft is flexible, the engines are large masses on long moment arms, the nacelles alter the local flow, and wing twist will change the local incidence and therefore the load distribution. That is exactly the kind of thing I am trying not to hand-wave.

The problem is that CFD is fragile. Langley Research Centre has a great many CFD tools, along with many gigabytes of utilities for helping work with them, and even then the engineers there needed years of experience to select what to use, when, and with what configuration to do anything useful. It's easy to give it sensible-looking values but get nonsense out.

So the idea is to use the historical reports as calibration points. If I can get wind-tunnel data for models, flight-test or service data for real airframes, and structural data such as wing load tests, torsional stiffness, elevator twist, tail twist, hinge moments, and stability reports, then the CFD/FEA model can be sanity-checked against a range of different scales.

CFD won't give me perfect results, whatever I do, which is why most places that do such work use a wide variety of methods, usually a mix that includes wind tunnels and CFD, and the company follows it up with building the real thing. At LaRC, for example, they have microphone arrays they use in wind tunnels there. Cords or tape were attached to the model, and they record the sound generated. I don't know what other facilities use, but I imagine they all measure a wide range of different things.

The best I'll be able to do is verify that what I'm seeing is consistent with what historic engineers who knew what they were doing and measuring saw and measured, on the assumption that this locks enough of the unknowns that everything I see beyond what they recorded has a bounded error. Since CFD is used and is useful, the values will be meaningful and usable, but only if the CFD is set up right.

 

[Jaivan]

In addition to everything available in the NA, there is the evaluation of flying qualities done by NACA:
Measurement of Flying Qualities of a Dehavilland Mosquito F-8 Airplane (AAF No. 43-334960) I: Lateral and Directional Stability and Control Characteristics
Measurement of Flying Qualities of a Dehavilland Mosquito F-8 Airplane (AAF No. 43-334960) II: Longitudinal Stability and Control Characteristics

 

[imipak]

In addition to everything available in the NA, there is the evaluation of flying qualities done by NACA:
Measurement of Flying Qualities of a Dehavilland Mosquito F-8 Airplane (AAF No. 43-334960) I: Lateral and Directional Stability and Control Characteristics
Measurement of Flying Qualities of a Dehavilland Mosquito F-8 Airplane (AAF No. 43-334960) II: Longitudinal Stability and Control Characteristics

Absolutely delightful information, thank you so much!

 

[Simon Thomas]

Mosquito Aero-elastic Distortion R&M 2371

 

[imipak]

Mosquito Aero-elastic Distortion R&M 2371

Thanks! That is greatly appreciated!