Greyhead

I wanted to add this as an edit to the last post but there doesn't appear to be an "Edit" button anymore!

Edit

Just got some more information, thanks Peter; the maximum speed with the 200h.p. Wolsey Viper was 138 mph so obviously they didn’t fall apart at 123 mph! At 18% that still works out OK for my model at just under 25 mph. not that I really want to fly at maximum speed, I prefer low slow passes!

Strange, I've just added this because the "Edit" button is on this post, but still not on the previous posts???

Greyhead

On the last trip to the field it was a flat calm, very unusual for our Redmarshall site.

As expected the take off run was considerably longer than on previous occasions, although the grass is kept short, at scale it is still the equivalent of taking off in a field of mowing grass so there is plenty of rolling resistance. If the model is taking off into a 5 mph wind then the airspeed is 5 mph faster than the ground speed; it even has an air speed of 5 mph when standing still!

What did surprise me was the rate of climb, or lack of it, once the model left the ground. In fact by the time it had gained sufficient height to make a turn I was quite concerned that it was so far away that orientation would soon become a problem. This is where I made an “error of judgement”; I turned the model to the right. The model lost some height executing the turn and was now only just visible above the hedge line, then I realised in the direction the model was now travelling the ground was rising at a gradient about the same as the models rate of climb so there was insufficient height to make another turn, so I closed the throttle and set the model down in the middle of the barley field.

When I got the model back I tried adjusting the needle valve just in case the engine wasn’t quite “on song” but it had no effect. I tried again; this time I was better prepared and had a successful flight but I’m going to try a smaller diameter prop to increase the engine revs, hence the maximum air speed, because although the model flies OK it is obviously marginal.

I’ve ordered an APC 15x4 but I’m going away in the caravan for a week so it’ll be after that before I can test it; watch this space!

Bunkerbarge

My heart was in my mouth reading this post and I thought for a second that you had lost it!

It makes sea trials seem quite a sedate affair compared to a maiden flight.

__________________

“Dirty British coaster with a salt-caked smoke stack, Butting through the Channel in the mad March days"

Greyhead

I would imagine the first trials with a boat are slightly less nerve racking than with an aircraft, presumably so long as the model doesn’t sink there’s not a lot that can go wrong that would be terminal.

Having said that I remember my brother and myself converting a model cabin cruiser to radio control when we were lads. It was the old single channel radio gear with a rubber-powered escarpment, no servos in those days!

Everything worked fine in the bath so it was off to Abbey Park pond. We sent the model straight out from the bank, press and hold the button and the model turned right, release and straight ahead. So far so good, another press and a left turn started, release the button, the model continued to turn left and proceeded to complete left hand circles gradually getting further and further from the bank.

Luckily not far away was the paddling pool with several kids in bathing trunks; a bit of bribery soon got one the lads to agree to a trip in the big pond to recover the model. He waded out and got hold of the model but on the return leg to the bank he decided it would be easier to swim, the problem was he did a very rough version of the crawl! Our shouts were to no avail and the model was duly returned full of water.

Surprisingly enough we took the circuit board out from the case, put it in the oven on a low heat and it was soon back working as good as it ever did, which isn’t saying a lot!

After that we went back onto aircraft. Although the models usually crashed, they were relatively cheap, it was the radio gear that was expensive, we thought we were very lucky to get away with one thorough soaking and didn’t want to repeat the experience.

Bunkerbarge

Just as a little smile to everyone and to remind you of how easily things can go wrong there is a little story with the attached pictures.

I bought this Joffre off eBay a year or so ago with the intention of tidying it up a bit and using it with my Envoy as she is the same scale and roughly the same period. Anyway the internals were a bit on the loose side and I had trouble getting it to work so it stayed on the shelf until yesterday when I thought I would give it a trial.

I fitted a new reciever, a new speed controller and a new 7.2 Tamiya pack, bought only last weekend at Harrogate. Tried it out and it all worked fine but the motor did seem a bit firece. Stuck it in the bath and she sat a bit low but bang on the water line so took it down to the pond this morning and tried it out. Sure enough the motor was too much and at full throttle she dug in a bit and pushed the bow down more than I would really want, especially with the freeboard not being too great. So a couple of things to do but she looked good and I was pleased that an internal strip out would give me a nice model.

The last five minutes and a couple of kids turn up asking about the boats so I said I would put the tug back in and show then how it worked. I went right across to the other side to the point where I can't see exactly what is happening and started to bring it back when I thought, "She looks a bit low!" A couple of seconds later and she looked even lower!!! A couple of seconds later and up went the stern and down she went!! A hush went over the crowd as everyone looked at the little loose dingy bobbing around in the water, all that was left to show where it had been.

I was more annoyed at the loss of the new speed controller, reciever and battery pack than anything else but the loss of a boat is always dissapointing as well. The lads all suggested I get the club boat out and go for a bit of fishing, which I really thought was a waste of time but I gave in and thought I'd have a go. I paddled around for a half an hour or so fishing with the grappling hook and rope, amid cries and jeers from the bank as to where everyone thought it had gone down. To my amazement I snagged it and brought it up, mostly intact, but with a couple of pieces missing and a few broken bits. Would you believe the propeller was still turning!!

Anyway lessons to be learned:

1) If it looks low in the water, you're probably right, remove some ballast!

2) If the motor is too powerfull, it probably is, slow it down!

3) If the deck coamings look low, they probably are, build them up!

4) If you notice all three at the same time, don't put it in the water!

At least I provided some light relief and entertainment for a half an hour or so and I am now forced to "Tidy Up" the model whether I want to or not. I've given the electrics a wash out with distilled water and they are now drying out so I might be lucky there.

Anyway I'm glad I got a couple of shots of her first, I at least know how to put the mast back together!!

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__________________

“Dirty British coaster with a salt-caked smoke stack, Butting through the Channel in the mad March days"

Biplan

Excuse me for popping in like this, but I just found this forum and thread.
According to an SE5a ace, Ira Jones, the plane could reach nearly 200 MPH in a dive. I've read the first half (about WWI) of his book "Tiger Squadron", first printed in 1945, numerous later reprints. The better part of the first half contains Ira's diary.

A short resume about Ira is found here: James Ira Thomas Jones - The Aerodrome - Aces and Aircraft of World War I

Tom
Oslo, Norway

Greyhead

Richard

Very nice photos, she looks really well on the water and I hope you’re as lucky with the drying out as we were. With modern encapsulated electronics I think you stand a very good chance of things working OK, except perhaps the servos as these have a degree of mechanical parts.

Tom

I’ve had several comments about the maximum speed for an SE5a and you’re absolutely right my 123 mph is way too slow. Information I’ve received suggests that they could in fact reach 225 mph safely in a dive, I say safely because presumably the pilots survived to tell the tale! I have realised where I made the error; I was quoting from an article about the Shuttleworth restored SE5a and the 123 mph must be the maximum speed that this is allowed to fly at these days, obviously they’re going to be very, very careful with such a valuable machine. I assume that the take off and landing speeds are comparable to WW1 days.

Anyway, welcome to the forum and I hope you find it interesting, any more information you may have about the SE5a will be gratefully received.

Grahame

Biplan

I've now got to page 6 of this thread and I'm learning a lot. I made a typo in post #656, the year is 1954 (the edit button does not appear although I'm logged in).

I've read somewhere - can't find it again, maybe it was just a beeline to a photo - that the dihedral was reduced at some point during the production.

Greyhead

Just to bring you up to date on a couple of modifications to the SE5a.

I had bent the axle to give a few degrees of toe-in. It did improve the tracking initially but because of an unforeseen flaw in the design I’ve now straightened the axle again.

The axle passes through holes in the undercarriage legs and is held by bungee cords. Having bent the axle it was slightly “V” shaped and was positioned in contact with the base of the axle fairing with the apex of the “V” pointing to the rear to give toe-in. When I checked after a couple of flights the axle had rotated, the “V” was now pointing forwards, giving toe-out, exactly what I didn’t want! Presumably the friction in the wheel bearings produced enough torque to overcome the friction of the bungee cords, the ground handling wasn’t too bad before, especially for a model of this type, so I decided to abandon the idea.

I moulded the noses of the bombs from rubber both for safety and to make them less prone to damage; however, the rubber I used has proven to be very susceptible to the affects of fuel / exhaust emissions, the detailing has virtually melted away and they are very sticky.

I have replaced them with some dome shaped rubber feet from Maplin Electronics, they are made from much more robust rubber so I hope they will not suffer the same fate.



As you can see from the photo the new noses are not the correct shape, are slightly too small in diameter and have no detailing but you have to be pragmatic about these things.



I think they are quite acceptable especially with the arming vanes in place and when seen from a distance slung under the model.

maratia

Fantastic!!!! Great job!!! Its wonderfull !!!
I never saw one airmodel with as many details as this !!!

Angelo, from Porto Alegre city, Brasil.