Parnall Elf

[Greyhead46]

Well it’s took some time but at last I managed to get myself, photographer and weather all to co-operate so here are a few flying shots. Hope you think it’s been worth the wait!

Take off

 

Banking right



Straight and level

 

Over the top

 

On finals

 

and a "fuzzy” shot of touchdown; it was just too far away from the camera!

 

 

But things didn’t all go according to plan!

[Manish Chandrayan]

Looks lovely,👏👏👏 does it not? Well worth all the trials and tribulations. That is what scale modelling is all about 👍 

[Greyhead46]

Hello Manish

 

I have to agree with you, a scale model flown in a scale manner to me is the pinnacle of aeromodelling.  It may not be as eye-catching as the 3D fliers but it takes a lot of practice and to be honest the "banking right" photo above is about as aerobatic as it gets!

 

Grahame

 

 

When I started the Laser at the “photo shoot” it was quite noisy but having travelled 160 miles to get to the flying site there was no way a bit of noise was going to stop the flying! During the session the noise level gradually increased and on the 4th start exhaust fumes started to exit via the cockpit; those of you who have followed this thread may recall that I made a remote silencer that up to date had performed very well but something was obviously amiss.

The exhaust system consists of about 6” of stainless steel flexible pipe connected to the silencer by a short length of silicone tube reinforced by braided stainless steel. The silicone tube has completely failed, I assume the missing bits must have been blown out through the silencer.

The hot exhaust gasses eventually burned a hole right through the firewall, hence the fumes from the cockpit

Both aerobatic and funfly models use these silicone tubes extensively to join the exhaust to the “tuned” pipe but not enclosed inside a cowl; the reduced airflow and the resulting increase in temperature obviously proved decisive.

A re-design of the exhaust system is called for and a fair amount of repair work to the firewall so no flying for a while (with the Elf at least) but it could have been much worse, just behind the firewall there are a lot of wires for the radio equipment and of course the fuel tank; the Elf could have come to a spectacular end!

 

The damage is not as bad as I’d first feared, what I thought was completely degraded wood turned out to be the remains of the anti-vibration foam. Yes there is a hole through the firewall (an appropriate name as it happens!!) but the main structure is still sound. There is some delaminating of the ply but having removed all the charcoal and giving it a thorough soaking with super-thin cyano it’s now as strong as ever.

The only thing inside the fuselage is a bit of scorching of the wood and the insulation on the power lead has turned brittle. Luckily it’s not the battery lead itself but the switch harness lead so that’s easy and cheap to replace.

This repair shouldn’t take long, just a case of gluing a patch on both sides, but figuring out what to do with the exhaust system to stop this happening again may take a bit longer!

Modifying is nearly always more difficult than starting from scratch, in this case the silencer inlet and the flexible exhaust are slightly different diameters; this wasn’t a problem when they were joined by silicone tube but I’ve had to use 3 different diameter tubes to join everything together.

As it is impossible to fit the exhaust as a complete unit it has to stay as 2 pieces, once again not a problem when they were joined by silicone tube. The “moveable” joint is a reasonably tight fit and has been sealed with car exhaust paste. On the test runs it’s sealed OK and I can now say that the exhaust works very well and there are no signs of the paintwork failing around the undercarriage.

 

[Murat Kece 1]

I can only admire when people take their works of art into air.. Well done.. You get my applause.

[Greyhead46]

Hello Murat

 

Thanks for the reply. It's always a testing time (no pun intended!) the first few times with a new model until things get trimmed but the satisfaction level when a model you've built, and more so if it's your own design is way up there.

 

Grahame

 

 

I suppose it had to happen; after 4 years of trouble free flying the Elf bit back today; of course it wasn’t the Elf’s fault it was mine!

It was one of those very rare days, really hot and a flat calm. The first flight was uneventful apart from a rather fast landing, which inevitably ended with the model on its nose; it’s amazing how much even a slight breeze slows the landing approach.

After watching a few other models flying I prepared for the next flight. By this time the windsock was behaving rather oddly, there was still no wind as such but every now and they the air “moved” and this movement was in random directions; could it have been caused by thermal activity?

I should have known better and changed to flying the ArcoWot, but the other models had had no problems; I opened the throttle but half way down the strip the Elf lifted a wing and cart wheeled along the ground.

It looked a sorry sight; one wheel bent up at 45º, one set of wings at very strange angles and warren girders sticking out every which way. I picked up the bits and did what I should have done earlier; I carried on flying with the AcroWot.

Having got the model home and had a chance to have a good look at it I can safely say it’s not as bad as it first appeared. Most of the bolts holding the Warren girders and cabane struts on one side of the model have sheared but having replaced them temporarily with twists of wire the wings are once again aligned correctly and they fold with no trouble. The axle bent back into position easily, the only real damage is to the rear of the fuselage just in front of the tail plane where some of the sheeting has split, this is not a structural part so it will be easily fixed with a drop of cyano.

I think I really got off lightly, although replacing all those bolts is going to be a tedious job.

 

The Elf is ready to fly again but we’ve got those strong winds back again, most frustrating! I found one more thing that was broken, the cockpit bulkhead, which holds the compass and a couple of switches. It’s not a structural part of the fuselage, it’s only for scale detail and will be quite awkward to replace so I’ve deferred that job for now.

Replacing the 14BA nuts and bolts went a lot easier than I thought it would from my experience of doing the job originally. What made the difference this time was that I had fitted the Warren girders in place temporarily with thin wire.

The Warren girders are the only things holding the wings in the correct positions relative to each other. The first time I did the job I fitted one Warren girder, then the next and so on, this meant that the wings tended to move about as I worked on them making life rather (very!!) difficult. This time I locked the wings in position with the carbon fibre “tongues”, removed one Warren girder at a time, which left 5 still holding the wings, fitted this one with the 14BA nuts and bolts and then removed the next. Whilst still not the easiest of jobs it was a lot better and is a lesson learned for the future.

 

The End of an Era

After giving me much pleasure over many years, both building and flying, the Elf is now on its way to a new home, in South Africa! Deciding whether or not to sell the model was not an easy task as she really is a “one off”.

The offer came just as we had sold our house and storage was a real issue, some things just had to go and of course I’ve now got the SE5a to play with. It was a toss-up between the Elf and the wife but the thought of eating beans on toast for the rest of my life swayed me towards parting with the Elf and in all honesty I don’t think I’d have got as much for the wife!

Edited May 28, 2023 by Greyhead46

[paul devereux]

So, you sold it? Was it bought as a flying model or as a display model for an organisation? 

[Basil]

19 hours ago, Greyhead46 said:

Hello Murat

 

Thanks for the reply. It's always a testing time (no pun intended!) the first few times with a new model until things get trimmed but the satisfaction level when a model you've built, and more so if it's your own design is way up there.

 

Grahame

 

 

I suppose it had to happen; after 4 years of trouble free flying the Elf bit back today; of course it wasn’t the Elf’s fault it was mine!

It was one of those very rare days, really hot and a flat calm. The first flight was uneventful apart from a rather fast landing, which inevitably ended with the model on its nose; it’s amazing how much even a slight breeze slows the landing approach.

After watching a few other models flying I prepared for the next flight. By this time the windsock was behaving rather oddly, there was still no wind as such but every now and they the air “moved” and this movement was in random directions; could it have been caused by thermal activity?

I should have known better and changed to flying the ArcoWot, but the other models had had no problems; I opened the throttle but half way down the strip the Elf lifted a wing and cart wheeled along the ground.

It looked a sorry sight; one wheel bent up at 45º, one set of wings at very strange angles and warren girders sticking out every which way. I picked up the bits and did what I should have done earlier; I carried on flying with the AcroWot.

Having got the model home and had a chance to have a good look at it I can safely say it’s not as bad as it first appeared. Most of the bolts holding the Warren girders and cabane struts on one side of the model have sheared but having replaced them temporarily with twists of wire the wings are once again aligned correctly and they fold with no trouble. The axle bent back into position easily, the only real damage is to the rear of the fuselage just in front of the tail plane where some of the sheeting has split, this is not a structural part so it will be easily fixed with a drop of cyano.

I think I really got off lightly, although replacing all those bolts is going to be a tedious job.

 

The Elf is ready to fly again but we’ve got those strong winds back again, most frustrating! I found one more thing that was broken, the cockpit bulkhead, which holds the compass and a couple of switches. It’s not a structural part of the fuselage, it’s only for scale detail and will be quite awkward to replace so I’ve deferred that job for now.

Replacing the 14BA nuts and bolts went a lot easier than I thought it would from my experience of doing the job originally. What made the difference this time was that I had fitted the Warren girders in place temporarily with thin wire.

The Warren girders are the only things holding the wings in the correct positions relative to each other. The first time I did the job I fitted one Warren girder, then the next and so on, this meant that the wings tended to move about as I worked on them making life rather (very!!) difficult. This time I locked the wings in position with the carbon fibre “tongues”, removed one Warren girder at a time, which left 5 still holding the wings, fitted this one with the 14BA nuts and bolts and then removed the next. Whilst still not the easiest of jobs it was a lot better and is a lesson learned for the future.

 

The End of an Era

After giving me much pleasure over many years, both building and flying, the Elf is now on its way to a new home, in South Africa! Deciding whether or not to sell the model was not an easy task as she really is a “one off”.

The offer came just as we had sold our house and storage was a real issue, some things just had to go and of course I’ve now got the SE5a to play with. It was a toss-up between the Elf and the wife but the thought of eating beans on toast for the rest of my life swayed me towards parting with the Elf and in all honesty I don’t think I’d have got as much for the wife!

Thank you for such a super thread in so many ways. Inspirational, quality that I am never going to achieve, but I strive.

Bas

 

[David Holland 2]

Another build thread please, Greyhead, I'm missing my "fix"!!

[Greyhead46]

Thanks for the replies.

 

Paul: The offer to buy came “out of the blue”, I hadn’t advertised or anything, it was a post on the original build thread so I assumed it must have come from a modeller but later, after it had arrived in South Africa, I got another post asking where the propeller was (didn’t seem to realise it needed an engine) so I don’t know?

 

Basil: There’s nothing too hard about it, I just break the build down into sections, if you do the best you can with each section you’ll have a model you can be proud of! The more you do the easier it gets so just keep building, you’ll get there.

 

David: I don’t think I’ll be doing another thread, both the Elf and the SE5a were built some years ago and arthritis means my hands just don’t work very well now.

 

Grahame

                                                                                                                                              

[paul devereux]

7 hours ago, Greyhead46 said:

Paul: The offer to buy came “out of the blue”, I hadn’t advertised or anything, it was a post on the original build thread so I assumed it must have come from a modeller but later, after it had arrived in South Africa, I got another post asking where the propeller was (didn’t seem to realise it needed an engine) so I don’t know?

                                                                                                                

Not a modeller then, as they would be more knowledgeable. It is a display model. Which is more of an endorsement of your skills, really.

[Greyhead46]

Hello Paul

 

I suppose so but I really think aeroplanes, be they model or full size (Vulcan!) belong in the air!

 

Grahame