Scale flying, what's right and what's wrong

[PatMc]

20 minutes ago, Martin Harris - Moderator said:

But if it’s at say 20 - 30 knots the spread of bullets would probably hit the engine, fuel tank and pilot as it was passing overhead without any return fire to worry about and disturb the aim.  Firing at a high AoA well above the normal stall angle would give bullets more chance of hitting something vulnerable too. 

Only if the target aiircraft is flying almost exactly in an up or downwind direction or there's virtualy no wind.  

I go with the stall turn/wingover as being most likely.

[Peter Miller]

2 hours ago, Simon Chaddock said:

The DVIII did not need a 1:1 thrust to weight ratio but could approach the opponent in a steep climb where its docile stall characteristics allowed the pilot to confidently hold this attutude longer than any allied fighter.

From Wikipedia. 

"The D.VII was also noted for its high manoeuvrability and ability to climb, its remarkably docile stall and reluctance to spin. It could "hang on its prop" without stalling for brief periods of time, spraying enemy aircraft from below with machine gun fire. These handling characteristics contrasted with contemporary scouts such as the Camel and SPAD, which stalled sharply and spun vigorously."

The DVII could hang on its prop briefly before falling away.  It had to do this at times  because the the De Havilland DH 4 had a higher ceiling of 22000 plus feet. which was much higher than the Fokker could reach.  

I have the best possible evidence of this...My father was an observer on DH4s and this was proved on his last flight when his  aircraft was shot down.  (He had 6 official "kills" from the back seat of the DH4) Yes, they just made it over the lines and in that fight he was badly shot up and spent  13 months in hospital.

 

[GrumpyGnome]

3 hours ago, Ron Gray said:

I’d be quite happy to see a model DVII go into a vertical / steep climb, slow down, hesitate then either complete a stall turn or wing over. I wouldn’t like to see it prop hang for a more than couple of seconds at the top of the climb!

 

Yup

[Mike T]

Given it's power and similar benign/stall handling characteristics, I'm pretty sure S.E.5s could have done this if the need/opportunity arose

[Martin Harris - Moderator]

On 02/09/2023 at 12:15, PatMc said:

Only if the target aiircraft is flying almost exactly in an up or downwind direction or there's virtualy no wind.  

I go with the stall turn/wingover as being most likely.

What on earth (that’s rather inappropriate terminology!) has wind got to do with it?

[PatMc]

Surely if the attack aircraft is prop hanging it will be at the mercy of the wind speed & direction.

[Martin Harris - Moderator]

The target aircraft is in the same air mass so wind speed can be ignored!

[Geoff S]

16 minutes ago, Martin Harris - Moderator said:

The target aircraft is in the same air mass so wind speed can be ignored!

 Exactly. It's just like sailing in a current - it's only differences in current that affect a yacht's progress relative to others - and that requires separation.

[Simon Chaddock]

On 04/09/2023 at 17:05, Mike T said:

Given it's power and similar benign/stall handling characteristics, I'm pretty sure S.E.5s could have done this if the need/opportunity arose

I think you are overlooking the fact than the DVII had catelever thick section wings with no bracing and a section similar to GOE 298.

 

The SE5 like all allied fighter of the time used a thin undercanbered section (RAF-19?) so needed bracing.  The stall characteristics were rather different.

A typical allied braced biplne section.

Edited September 6, 2023 by Simon Chaddock

[Mike T]

To pursue Martin's line of enquiry - why on earth would the wing section matter to an aircraft hanging on its prop? 🙂  I can't see that the stall characteristics have anything to do with it.  The Wolseley SE had about 220HP; the BMW DVII about 185.

[Martin Harris - Moderator]

I understand that it was the more benign slow speed handling of the more modern aerofoil that allowed the brief prop hang and reliable recovery to normal flight.

[Simon Chaddock]

None of the WWL planes could prop hang as we understand in current RC practise.

The best they could do was to approeach at a steep angle, not truly vertical and hold it pointing at the target plane until the plane had slowed down to the point the available thrust could not over come the weight. At this point in allied fighters the most likely result would be a spin resulting in at best in a significant loss of height. In addition spin recovery was not guaranteed hence the edict at the time "Don't stall".

The DVII stall recovery was virtually at modern standards so level flight could be regained quicky giving the possibility of having another go at the target.

 

It is perhaps worth noting that the overall performance of the DVII was such that the Armistice document specifically stated that Germany was required to surrender all D.VIIs to the Allies.

[Jon H]

1 hour ago, Simon Chaddock said:

None of the WWL planes could prop hang as we understand in current RC practise.

The best they could do was to approeach at a steep angle, not truly vertical and hold it pointing at the target plane until the plane had slowed down to the point the available thrust could not over come the weight. At this point in allied fighters the most likely result would be a spin resulting in at best in a significant loss of height. In addition spin recovery was not guaranteed hence the edict at the time "Don't stall".

The DVII stall recovery was virtually at modern standards so level flight could be regained quicky giving the possibility of having another go at the target.

 

It is perhaps worth noting that the overall performance of the DVII was such that the Armistice document specifically stated that Germany was required to surrender all D.VIIs to the Allies.

 

Agreed. I think it was more of a delayed prop assisted vertical flop than any sort of prop hang and suspect the biggest factor allowing it to happen was the use of an inline engine and not a rotary as the gyro effects would make that sort of thing virtually impossible. 

[Martin Harris - Moderator]

What did I start with a light hearted comment over a non scale manoeuvre by an otherwise respected scale flyer of great repute!

 

The torque effects are certainly a very significant factor in limiting this manoeuvre to non-rotary engines.

[Mike T]

1 hour ago, Martin Harris - Moderator said:

What did I start with a light hearted comment over a non scale manoeuvre by an otherwise respected scale flyer of great repute!

I think it's called 'a debate' - the life blood of internet forums! 🙂

 

I take the point about post-manoeuvre stall characteristics.  If the consequential effects of any particular manoeuvre are more trouble than their worth, then that's a huge disincentive to execute it in the first place.   FWIW, I always imagined the DVII's performance of this trick was somewhat like a slightly delayed stall turn, with enough time at the top to fire off 20 or so rounds before falling away.

 

Re the naming of DVIIs in the Armistice, I think this is because at the time it was considered the most significant threat in the Luftstreitkraefte arsenal.  If the war had gone on another 6 months, the Armistice might well have singled out e.g. the Pfalz DXII.   Note that post-war, the two aircraft that found their way into other nascent air forces in significant numbers were the DVII and the SE5.

 

 

[Chris Walby]

Thanks to those that posted, if at times slightly off topic 😉

 

And following on from this thread and a couple of days at Buckminster Scale Comp (chatted with Chris Allen and a few other fliers) I now have a better understanding of the scale comp requirements and scale flying (full size or model). As with things in life they are a bit more complicated or if a Douglas Adams fan (if you don't ask a specific, then you won't get a specific answer!) sort of thing. From what I can gather scale flying relies on the pilot having done the research on that type of aircraft and then their selection of manoeuvres to best demonstrate their skill and the performance of the full size aircraft. Now this is where there are a hole load of rabbit holes to disappear down, but I'll side step them as there is a word count limit on posts.

 

The answer (for me) lies somewhere in pilots notes, performance and design specifications for the aircraft of interest and any other technical information for the full size. Its raised a few other questions like whether something should be demonstrated when for the full size is strongly recommended not to do it e.g. aircraft that have very poor spin recovery, so just because you can do it with the model and its within the rules, it would not really be good form to do it in your routine. Just don't mention loops - another rabbit hole/discussion point..

 

For basic flying like circuits and figures of 8 it seems simple, but then it all changes, well becomes more aircraft specific as to how the manoeuvre is executed. Rabbit hole warning!

 

So thanks for all the info and it looks like I have a lot of bedtime reading in the future 🙂 and a load more flying! 

 

[PatMc]

On 06/09/2023 at 10:17, Martin Harris - Moderator said:

The target aircraft is in the same air mass so wind speed can be ignored!

You're right, of course, Martin. Complete woolly non thinking on my part. 

But I think the idea of a D7 prop hanging & spraying enemy aircraft from below with machine gun fire is total fantasy. Even the slowest likely target aircraft, e.g. the much loathed R.E.8, would be travelling at at least 60 mph, making only one or two rounds even likely to hit it during the time available. The odds of a vital strike would be pretty poor compared to the conventional already proven tactics of the time.

 

Back on track - Chris, one book that details an aerobatic display with a Spitfire is Sigh For a Merlin by the well known test pilot Alex Henshaw, The display being for the benefit of Winston Churchill who was hosting a group of, IIRC, US politicians & military officers.

OTOH I think it was Pierre Clostermann in his book The Big Show that makes the point that any pilot doing aerobatics in a war zone is making himself a potential easy target. 

With this in mind I think if a war plane is in clean factory fresh condition aerobatics would be in order (though IMO not precise model aerobatic contest standard). But if the model is presented dirtied up to represent an in service operational machine the flying display should be more just tight turns & zooming around plus of course standard take off, procedure turns etc      

[Peter Miller]

10 hours ago, PatMc said:

But I think the idea of a D7 prop hanging & spraying enemy aircraft from below with machine gun fire is total fantasy. Even the slowest likely target aircraft, e.g. the much loathed R.E.8, would be travelling at at least 60 mph, making only one or two rounds even likely to hit it during the time available. The odds of a vital strike would be pretty poor compared to the conventional already proven tactics of the time.

Try tell that to my late father (see above)

It would pull up and fire a brief burst before falling away.

On the particular raid 9 aircraft were sent to bomb a bridge. Orders were to bomb the bridge and climb for height.  Three never took off, 3 turned back due to engine problems.

3 bombed the bridge.Two turned back but disobeyed instructions to climb....they never made it back.My father's pilot climbed for height.  See my previous post on this subject as to the final result.

Quite frankly I think I would trust the accuracy of my father's description of events rather than all the theories being posted on this thread. After all, he was there!

[Ron Gray]

Your father’s accounts would tend to back up the theory of it not prop hanging but it being more of a stall turn but in all probability more of a stall nose over where the benign nature of the DVIIs stall would allow it to just drop its nose without any fear of entering a spin. That, to me, seems to be the most likely manoeuvre.

[Peter Miller]

It certainly was NOT prop hanging.  What most people seem to have missed with their comments of "only a couple of rounds"

 is that the Fokker DVII would have come up under the DH4 and started firing as it raised its nose.  The bullets would have started hitting the DH4  from somewhere towards the front and tracked back along the fuselage.

Consider that my father had several bullets in his lower right leg (THe scarring was in the shin from just below the knee down towards the ankle. He also had a bullet in his right elbow (Could never fully straighten his arm) and a bullet through his right shoulder.

So much for "just a couple of bullets" although some could have been from and earlier attack.  Incidentally he also shot off his own aircraft's rudder horns but luckily the DH4 also had secondary rudder horns which still allow some rudder control.

 

In another battle another incident. After the fight the pilot held up his right hand.  The forefinger and index finger where hanging loose. He then held up his left hand and the same fingers of that hand where hanging loose. Bullet had smashed into the top of the control column.  I believe that that pilot was madam Tussaud's son. Although I could b wrong.I know one of his pilots was that man.

[PatMc]

4 hours ago, Peter Miller said:

Try tell that to my late father (see above)

It would pull up and fire a brief burst before falling away.

On the particular raid 9 aircraft were sent to bomb a bridge. Orders were to bomb the bridge and climb for height.  Three never took off, 3 turned back due to engine problems.

3 bombed the bridge.Two turned back but disobeyed instructions to climb....they never made it back.My father's pilot climbed for height.  See my previous post on this subject as to the final result.

Quite frankly I think I would trust the accuracy of my father's description of events rather than all the theories being posted on this thread. After all, he was there!

Peter, I don't think we are disagreeing, I think we are considering different scenarios. I have only cast doubt on the "spraying with bullets whilst prop hanging" quote. 

Edited September 11, 2023 by PatMc

[Martin Harris - Moderator]

I suspect that contemporary reports of prop hanging may have referred to operating beyond the normal stall angle of attack by making use of its favourable power to weight ratio and benign stall characteristics.  It was certainly a significant enough manoeuvre to have gone on record as a technique particularly associated with the Fokker D VII...

 

Peter's description of his father's injuries suggests that it was able to hold station with enough angle to fire significantly upwards while maintaining aimed fire - maybe with sufficient control to alter pitch as the distance changed.

 

To reiterate, I wasn't suggesting seriously that the D VII was capable of sustained vertical prop hanging a la the 3D models we see emulating demented helicopters - just that the D VII might have inspired Mr Redshaw to emulate their manoeuvre in a moment of untypical scale aberration!

 

Do we have any different advice to offer on more typical scale flying?

[Mike T]

32 minutes ago, Martin Harris - Moderator said:

Do we have any different advice to offer on more typical scale flying?

Yes.  It helps to have the right prototype.  Take the "Spirit of St Louis".   

 

An accurate scale flight would involve a protracted take-off run, then keeping low, head east until out of sight.  Guaranteed maximum points.  The only flaw I can see is that it may not be possible to participate in subsequent rounds...

[Chris Walby]

So picking on a Fokker Dr1 as an example

Scale

• Take off - bring the tail up prior to lifting the main wheels and a very gentle climb out
• Landing - main wheels, hold tail up and use rudder to control yaw/direction 
• Figure of eight
• Descending circle
• Chandelle
• Split S
• Roll (with ascending entry and descending exit)
• Barrel roll (with ascending entry and descending exit) 
• Wing over
• Scissors - or the normal way I fly!

Not scale

• Bunt
• Axial roll (like if I could!)
• English bunt

 

How about 

• Spin?
• Half Cuban Eight
• Cuban Eight
• Stall turn

Agree, disagree or just add one of your own (explaining how its performed!) Cheers

[Martin Harris - Moderator]

Sideslip approach with use of blipped throttle if appropriate?