Did the 190D-13 have hydraulic ailerons?
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The claim of hydraulic boosted controls comes from a book by Jerremy Scutts called "Yellow 12" which is about the restoration of a Fw 190D12. Apparently after its transport from Europe to the US the Fw 190D12 had been incorrectly mated, or rather shoe horned to a Fw 190D9 wing. When the correct wing was installed the rebuilders noted that there were extra conduits in the D12 wing that were not in the D9 wing. They seemed to think these were from hydraulically boosted ailerons.
One could describe the Fw 190D12 as a Fw 190D9 with the Jumo 213A1 engine (which had a single stage two speed supercharger) replaced with the Jumo 213F (or latter 213E1 or 213EB) all of which had two stage three speed superchargers, the latter two with inter-cooling. Also noteworthy is that the D12 and D13 deleted the cowling guns and instead came with a 30mm canon in the propeller hub (in case of the D12) and 20mm (in the case of the D13, the only difference) for a total of 3 canon.
It doesn't seem to be correct, at least not certain, because last I checked on bulletin boards the kind of folks that work on these or access to the aircraft in the museum were looking for other evidence such as hydraulic pumps mounted on the motor. Clearly there was likely a pump to operate the retraction mechanism and flaps. By this time the Fw 190 seems to have switched from electric mechanism for flaps and undercarriage retraction to hydraulically, presumably to save copper or lead.
All one needs besides the normal control cables is a pair of hydraulic lines and a combined servo-valve and servo cylinder at the aileron itself. If the hydraulic pressure fails a spring loaded pin locks the control cable directly to the control surface. These are 'boosted' controls where pilots still provides effort (18% in the P-38J I believe). Controls refered to as 'irreversible' whereby the hydraulics provide 100% of the effort became essential in the jet era because of pilot coupled oscillations. These need to be 'tensioned' in proportion to dynamic pressure (indicated airspeed) to provide artificial feel and really need a stick shaker connected to a angle of attack instrument to warn of stall. We need those aileron hydraulic cylinders to be sure.
The only German aircraft I am fairly certain had hydraulic boosted controls was the rather massive Dornier Do 335. I have seen point blank statements that the He 162 had them (to avoid lock up at Mach) but I doubt it given the simplicity of the aircraft, the aircraft did however have an undercarriage that lowered by spring force but raised by hydraulic force which required near full power to raise the undercarriage. Many aircraft of the era had what are called servo tabs where by a small tab on say the aileron is operated by the control stick or column and that then deflects the larger surface. These are note to be confused with balance tabs or trim tabs which work and look similar but serve a different purpose. Servo tab mechanisms can easily be confused with hydraulic assist. The problem with servo tabs is that the can become too effective at high speed unless carefully designed and they are vulnerable to flutter. Usually very complicated with an elaborate rigging of springs and leavers. Problems with adjusting these on the F.21 series spitfire for the elevator lead to the infamous RAE "no further effort should be expended in developing the type" assessment although the issue was solved.
It's certainly possible, the Germans were clearly aware of the issue and there is some discussion in the book "Messerschmitt Sercret Projects" into the likely need of boosted controls on the new generation of jets.
The roll rate of the 190 was excellent but it definitely fell off after 350mph.
One could describe the Fw 190D12 as a Fw 190D9 with the Jumo 213A1 engine (which had a single stage two speed supercharger) replaced with the Jumo 213F (or latter 213E1 or 213EB) all of which had two stage three speed superchargers, the latter two with inter-cooling. Also noteworthy is that the D12 and D13 deleted the cowling guns and instead came with a 30mm canon in the propeller hub (in case of the D12) and 20mm (in the case of the D13, the only difference) for a total of 3 canon.
It doesn't seem to be correct, at least not certain, because last I checked on bulletin boards the kind of folks that work on these or access to the aircraft in the museum were looking for other evidence such as hydraulic pumps mounted on the motor. Clearly there was likely a pump to operate the retraction mechanism and flaps. By this time the Fw 190 seems to have switched from electric mechanism for flaps and undercarriage retraction to hydraulically, presumably to save copper or lead.
All one needs besides the normal control cables is a pair of hydraulic lines and a combined servo-valve and servo cylinder at the aileron itself. If the hydraulic pressure fails a spring loaded pin locks the control cable directly to the control surface. These are 'boosted' controls where pilots still provides effort (18% in the P-38J I believe). Controls refered to as 'irreversible' whereby the hydraulics provide 100% of the effort became essential in the jet era because of pilot coupled oscillations. These need to be 'tensioned' in proportion to dynamic pressure (indicated airspeed) to provide artificial feel and really need a stick shaker connected to a angle of attack instrument to warn of stall. We need those aileron hydraulic cylinders to be sure.
The only German aircraft I am fairly certain had hydraulic boosted controls was the rather massive Dornier Do 335. I have seen point blank statements that the He 162 had them (to avoid lock up at Mach) but I doubt it given the simplicity of the aircraft, the aircraft did however have an undercarriage that lowered by spring force but raised by hydraulic force which required near full power to raise the undercarriage. Many aircraft of the era had what are called servo tabs where by a small tab on say the aileron is operated by the control stick or column and that then deflects the larger surface. These are note to be confused with balance tabs or trim tabs which work and look similar but serve a different purpose. Servo tab mechanisms can easily be confused with hydraulic assist. The problem with servo tabs is that the can become too effective at high speed unless carefully designed and they are vulnerable to flutter. Usually very complicated with an elaborate rigging of springs and leavers. Problems with adjusting these on the F.21 series spitfire for the elevator lead to the infamous RAE "no further effort should be expended in developing the type" assessment although the issue was solved.
It's certainly possible, the Germans were clearly aware of the issue and there is some discussion in the book "Messerschmitt Sercret Projects" into the likely need of boosted controls on the new generation of jets.
The roll rate of the 190 was excellent but it definitely fell off after 350mph.
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Surely 'Yellow 10" W.Nr. 836017. Then USA 14/FE 118/T-2 118 to the Americans.
This D-13 fuselage definitely contains a hydraulic aileron boost. This is documented by Art Williams during the restoration undertaken in Germany on behalf of Doug Champlin. There was a change to hydraulically operated flaps (certainly for the Ta 152) but the people who have seen the installation in the fuselage and correct wings of the D-13 believe that boosted ailerons were to be fitted. Whether the system was operational or not we'll never know. Several late war aircraft, notably the Me 262, were fitted with elements of systems which were never fully installed.
Cheers
Steve
This D-13 fuselage definitely contains a hydraulic aileron boost. This is documented by Art Williams during the restoration undertaken in Germany on behalf of Doug Champlin. There was a change to hydraulically operated flaps (certainly for the Ta 152) but the people who have seen the installation in the fuselage and correct wings of the D-13 believe that boosted ailerons were to be fitted. Whether the system was operational or not we'll never know. Several late war aircraft, notably the Me 262, were fitted with elements of systems which were never fully installed.
Cheers
Steve
N4521U
Colonel
All they had to do was hang a "shovel" under the ailerons like a Pitts!
swampyankee
Chief Master Sergeant
- 4,022
- Jun 25, 2013
Servo tabs seem to have been well-liked by Boeing for a while: they were used on the B-17, 707, and early marks of the B-52. That last is especially surprising, as the B-47 had hydraulic flight controls.
A monster such as the B-36 could be controlled by servo tabs. I believe the 707 must have transitioned to power controls at some point. On the 727, which had hydraulic controls, servo tabs were available on the inner ailerons for when hydraulics failed. A lot of work in power and boosted control was done in the UK and one saw some very advanced work come out in aircraft such as the Bristol Brabazon and V-bombers. Decisive in the adoption of hydraulics is the greater ease of eliminating flutter: though there is an issue of ' micro flutter' tiny, imperceptible flutter on surface held stiff by hydraulics that can cause fatigue
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so this plane has not got hydraulic arilerons,and never had hydraulic ailerons?
Is there any German documents, saying that the D-13 had,or going to have hydraulic ailerons.
And can any one tell me what the handbook dive limit for the D-13,or any 190D come to that.
thanks Ian
Is there any German documents, saying that the D-13 had,or going to have hydraulic ailerons.
And can any one tell me what the handbook dive limit for the D-13,or any 190D come to that.
thanks Ian
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