BE2e Centre of Gravity Position.

[onetenor]

Post two from me as well

[David Davis]

Yes very interesting Peter. The De Havilland 9A, a development of the DH4 had an engine which could produce 400bhp quite an increase on the BE2's 90!

[DH 82A]

Full size aircraft with "tandem" cockpits, Tiger moth, Moth Minor, Jung mann, Chipmunk etc. balance on the region of the front (passenger) seat so the balance does not alter between passenger on board, and no passenger. So a scale(ish) model should balance similarly.

[MattyB]

Posted by David Davis on 29/11/2016 11:51:36:

Jon, to be specific, the model is extremely unstable. If you click on the link in my original post you can see a video of me flying the model in England in December 2014 if memory serves. The entire flight consists of erratic left-hand circuits.

Could you post a direct link to that video in this thread David? I did look for it on RCU, but could not find it - I suspect it may be one of those forums that only displays links if you log in, and I don't really want to become a member of any additional forums!

[David Davis]

Is this any better Matty?

**LINK**

Others have wondered what I am complaining about but they were not pushing and pulling on the sticks all the time just to keep the model in the air. The flight this summer was even worse with the aircraft going completely out of control at least once and a landing in which the model tipped over onto its nose.

I am going to try weight under the engine and will report back. I may have to fit the Thunder Tiger 91 and the lead as I seem to have exhausted my supply!

[Denis Watkins]

I am still mesmerised and drawn to that huge elevator David. 2 things. 1. If the C of G is rearward, then this model must be a nightmare to fly. 2. With the Tx sticks at neutral, as always, but especially with this model, those surfaces should have no play in them. Just 1mm of play, in those surfaces will result in flights as you have described, especially that elevator. Something is obviously adrift on this aircraft.

[john stones 1 - Moderator]

Elevator's part of the design, get c.g set right n correct amount of movement n it's no problem, looks to be loads of down trim on elevator and any increase in throttle noses pitchs up ? do's it all feel c.g related or might it benefit from some downthrust ?

John

[David Davis]

Posted by Jon Harper - Laser Engines on 03/12/2016 09:43:07:

you could also set up a flight mode on your radio so that at the flight of a switch you can make the full range of your throttle stick only move say 50% of the actual throttle range.

You still need full throttle available for tuning, and its there if you get into trouble so a flight mode might be a good option

So that's what "flight mode" means! I tell you I'm getting too old for this modern IT age!

John Stones, I had thought of adding some down-thrust but will make one change at the time.

[Biggles' Elder Brother - Moderator]

Flight modes are really useful and valuable Tx programming techniques. Tey basically allow you to have multiple set ups - at the flicj of one switch you change lots of things - so you could have different throtlle range, different control throws and different mixes - all change at once if that id what youy want.

Typically its used if you find that a different set up is good for, say, take-off or landing, than is the case for general flying aorund. So, for example, you can have a take-off flight mode that gived you:

1. More throttle range

2. Bigger up elevator throw to help keep the tail down

3. Reduced ailerons - or even slightly drooped off set ailerons to give a flap effect.

Then, once airborne, flick the switch and everything reverts to "normal" You could have other set ups (flight modes) for landing, or aerobatics, or switching in 3D mode with "barn door style control throws" or switch it out for procission aerobatics (not with the BE2 perhaps - but you get the general idea!). Flight modes are a very useful tool - especially so with a slight "nervous" model like this that might well respond well to different set up for different parts of the flight.

BEB

[MattyB]

Posted by David Davis on 03/12/2016 19:33:54:

Is this any better Matty?

**LINK**

Others have wondered what I am complaining about but they were not pushing and pulling on the sticks all the time just to keep the model in the air. The flight this summer was even worse with the aircraft going completely out of control at least once and a landing in which the model tipped over onto its nose.

Yep, that worked great thanks. Having watched it I agree it looks tail heavy to me; this is especially clear in the way it takes off. I would be very surprised indeed if additional noseweight doesn't tame it down nicely, though even with that you may be able to refine the handling further through small cabs he's to the thrust line and/or rigging angles of the two wings.

[David Davis]

I've decided that the problem lies with a c.g too far to the rear. I need to put a lot of lead under the engine. The c/g is close to the rear cabane struts as shown on the plan, however, several enthusiasts with a greater knowledge of aerodynamics have suggested that it should be several centimetres further forward, i.e, above the front cockpit.

I had a light lunch of sardines yesterday, without a glass of wine for the first time in ages but that's another issue! I looked at the empty tin and thought that it was just the right size and shape to go under the engine! I cleaned it out, put it on the small ring and melted over 500 grammes (18ozs) of lead into it. I then fitted it to the model with elastic bands to see what effect it would have. The c/g is now above the centre of the front cockpit. I have to work out how to attach the lead permanently. I'll report back.

[ted hughes]

Posted by Peter Miller on 03/12/2016 12:49:04:

Well they didn't know any better. My father did say that at that height it was almost impossible to swing his twin Lewis guns but the enemy fighters just could not reach them. It actually saved his life.

He was going on pilot training but volunteered to go with his pilot on this raid to bomb a bridge. 9 aircraft were to go. THree never took off, three turned back. Their order were to bomb the bridge and then climb for height. The other two simply turned for home...They never got back. MY father's pilot climed.

They were attacked by Fokker DVIIs ( He remembered a yellow DVII with a black chequerboard on the top wing)

They were badly shot up and my father was serious wounded but they got to the22,000 feet and eventually they crashed on our side of the lines.

I recently learned that he was officially credited with 6 kills from the rear cockpit.

He was also awarded the DFC for a very low level photo mission along a German canal

Edited By Peter Miller on 03/12/2016 12:53:26

Six kills- I believe you, but it seems hardly credible- he must have been very skilled!

[David Davis]

William Miller, a graduate of Durham University, is mentioned that on page 90 of "Above the War Fronts" by Norman Franks et al. He joined 18 Squadron in April 1918 after service with the Northumberland Fusiliers. He was flying with Captain Darvill DFC when the event that Peter describes took place. According to the summary in the book he is credited with five victories while flying with Lts Pickup and Pope and 2nd Lt Cuthbertson; four destroyed and one out of control shared with another crew.

Concerning flying at altitude in WW1I recall having a discussion about this with a member of my model flying club in England who was a doctor. I claimed that James McCudden had shot down several German reconnaissance aircraft from heights exceeding 20,000 ft. He claimed that no-one could have survived at those altitudes without oxygen. I found out later that he had been a doctor in the RAF for most of his medical career!

[Peter Miller]

His score was.

1 30 May 1918 in Dh 4 A8038 Pilot David Stawart Fokker DVII Destryed at Neuve Chapelle.

2 30 May 1918 " " " " " " " OOC Richebourg

3 8 July " " A7815 " George Darvilll " Destroyed Henin Lietard

4 28 July " " " " " OOC Vitry

5 4 Sept " " " " " " DESF Cantin

6 4 Sept " " " " " " DES Aubigny-au-Bac

Not sure what OOC and DESF stands for

The DH-4 ceilng was 22,000. Considering that the earliest ascent of Mount Everest 1922 three climbers reached 8000 meters or 26,246 without oxygen which was a lot harder work that sitting in an aircraft swinging guns I can't help feeling that your doctor was wrong regardless of his experience. and would prefer to believe someone who had actualy done it.

[David Davis]

Posted by Peter Miller on 16/12/2016 10:57:53:

His score was.

1 30 May 1918 in Dh 4 A8038 Pilot David Stawart Fokker DVII Destryed at Neuve Chapelle.

2 30 May 1918 " " " " " " " OOC Richebourg

3 8 July " " A7815 " George Darvilll " Destroyed Henin Lietard

4 28 July " " " " " OOC Vitry

5 4 Sept " " " " " " DESF Cantin

6 4 Sept " " " " " " DES Aubigny-au-Bac

Not sure what OOC and DESF stands for

The DH-4 ceilng was 22,000. Considering that the earliest ascent of Mount Everest 1922 three climbers reached 8000 meters or 26,246 without oxygen which was a lot harder work that sitting in an aircraft swinging guns I can't help feeling that your doctor was wrong regardless of his experience. and would prefer to believe someone who had actualy done it.

On the height issue I agree with you Peter.

OOC means Out Of Control. The enemy aircraft was apparently still intact but diving towards the ground in an uncontrolled manner, often an indication that the pilot had been killed or severely wounded.

DESF could mean destroyed by fire.

[Peter Miller]

Yes, I spotted "out of Control" after postng.

Fire was nasty Nasty but the Germans did have parachutes, unlike our people.

Edited By Peter Miller on 16/12/2016 12:13:34

[David Davis]

Indeed they did Peter, in the last months of the war.

However, to return to my model BE2e, here is a picture of the lead which I melted into a sardine tin. You can still see the shape of it quite easily! The kit has an under-cowling made of glass-fibre. I secured the lead to the under-cowling with silicon and a single bolt before fitting the assembly back into place using slightly larger wood-screws. This way if I need to add or remove lead it will be a fairly simple job. I will glass it permanently into place once I'm satisfied with things.

The second picture show the model inverted on the workbench. The forward piece of black Solartrim is at 12.5cms from the upper wing leading edge, the suggested balance point. At this point the model balances slightly nose-down. The other pieces of black trim show the c/g range as shown on the plan.

I'm not sure whether to test-fly the model myself or to give it to the best pilot in the club. This will involve binding a Mode 1 transmitter to the model but it's an idea.

[Peter Miller]

That is a serious lump of lead.

It should make the model far more docile than it was, that is certain. If you could fly it beforfe you certainly can now.

[David Davis]

Yes it's taken the weight of the model to 4.66kgs or 10lbs 4ozs. I think you're right, it's my model, I ought to test-fly it.

[john stones 1 - Moderator]

You have a feel for how it was David, who better to judge how it is now.

[J D 8]

I also think you should fly it David for the same reasons above.

Those early airmen could operate at 20,000 feet plus because they like some modern athlete's did altitude training by default on their normal operations/patrol's. Age was also on their side and I am sure if we tried it we would not last a minute. Cheers John.

[Jon H]

David dont forget that if you test fly it yourself you dont have to commit completely. As soon as it leaves the ground if it feels awful just chop the power and put it back down. Dont try and drag a moose into the sky, get out of it while only a few inches up

[David Davis]

Thanks for the advice gentlemen, I will indeed fly it myself. I've flown it before and I've flown Puppeteers and Baronettes so I should be able to manage. I'll let my colleagues know.

JD8, another thing to bear in mind was that that generation was generally physically fitter than we were even when we were young.

[Peter Miller]

Posted by David Davis on 16/12/2016 19:15:03:

JD8, another thing to bear in mind was that that generation was generally physically fitter than we were even when we were young.

I know that my father was a keen sportsman, played cricket and football for his university so he would have been fit. Mind you, after the trenches that fitness might have gone down a bit.

[Don Fry]

David, keep the faith. If you got it back before, a sardine of lead ain't going to be a problem.