How early could......

Hello! :D

This is the first thread/topic I've ever started. .... please be gentle.

Though I'd test the waters with something..... unique.

My hypothetical is:

How early could the Heinkel "Lerche" (Vertical take off and landing coleoptera) be built?

How long might it take to get into service after said prototyping?

Much cheers.
 

NoMommsen

Donor
Has there ever been a successfull implementaion (in the sense of satisfactory flying at least a prototype) of the coleoptera concept at all ?
 
At work.

Well..... the American tail sitters did get off the ground. The 'Anular wing' was successfully floown some time in the 1920's or 30's? (Not VTaL though)
 

trurle

Banned
The control problems of such aircraft would be overwhelming. Early VTOL aircraft all required multi-month training, and even with ace pilots accidents rate was high.
Engineering problems would be rectified well before the test pilots would be able to teach the first batch of the regular pilots.
Looking on cross-section, many problems are evident:
1) Too small landing gear to land in windy weather - can not land inclined without overturning.
2) 3-boom wing support - resulting in large ripple of control forces during yaw+roll or pitch+roll maneuvers. i.m.h.o., 4 booms will reduce the speed but improve handling during maneuvers much (30% ripple vs 50% ripple).
3) Large counter-rotating propellers are forcing aircraft to roll if and when damaged. And then the loss of control according to (2)
4) Limited FOV due pilot pose, cannot see threats in upper hemisphere clearly, and difficult to see target at all until last moments during typical bomber intercept mission. Well, i suspect aircraft can be rolled upside-down for intercept, but hanging on the harness belts for several minutes will clearly earn the "Lerche" the nickname "Neck-breaker"
Overall, i expect at least 12 months from first flight to transfer of 1st aircraft in combat. And it still will be very difficult to find a suitable pilots.
 
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At work.

*Nods and takes notes*

Never even knew/thought/etc about the 'Ripple of control surfaces'. Amazing.

So.... the machine was devised in desperation at the end of the war. I suppose to clarify my question:

Is there anything technically preventing some one of thinking/dreaming up this machine earlier?

What might the earliest year, given engine power limitations etc for 'A' Lerche to be devised?

*Of note: I believe Dornier did a lot of 'Prone pilot' experimentation in the test machine which they worked out the harmonic vibration problems with long extension drive shafts wich work went into the Do335? By all accounts the final.... 'Beds(?)' seemed to have been reported/recorded as comfortable...... ?
 
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trurle

Banned
At work.

*Nods and takes notes*

Never even knew/thought/etc about the 'Ripple of control surfaces'. Amazing.
Ripple of control force, not of control surface. Although control surface will also wobble because it is impossible to hold the stick absolutely rigidly. Imagine pushing the stick to roll aircraft, and unexpectedly stick will kick back in pitch direction. Simultaneously, actual pitch will change.
So.... the machine was devised in desperation at the end of the war. I suppose to clarify my question:

Is there anything technically preventing some one of thinking/dreaming up this machine earlier?
Yes. The immature technology of variable-pitch propellers (fixed-pitch propeller will reduce speed of such aircraft) and the gearboxes (need T/W=1 for VTOL, while T/W~0.1 at much higher speed for horizontal flight). Plus problems with engine overheat in transition mode, at low airspeed - mostly material tech with about heat-resistant alloys.
What might the earliest year, given engine power limitations etc for 'A' Lerche to be devised?
The Heinkel Lerche was built around DB-605 engine. Therefore, earliest possible date was 1942.
*Of note: I believe Dornier did a lot of 'Prone pilot' experimentation in the test machine which they worked out the harmonic vibration problems with long extension drive shafts wich work went into the Do335? By all accounts the final.... 'Beds(?)' seemed to have been reported/recorded as comfortable...... ?
May be. I would remain sceptical until really trying the cabin. The seating limiting pilot to neck movement, with spine in back impossible to turn (as expected for prone position), will definitely limit viewing angle, which is of primary importance for fighter or interceptor pilot. Well, i can imagine prone-seat with bearing ring in waist, but i doubt it was implemented or practical to implement due high g-loads in the fighter. Need not just bearing, but sort of exo-skeleton to actuate such a seat.
 
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