Bates 1/5.5 Sea Fury Build

[Nick Somerville]

Some work at the front end today. The fuel tank position took a little time to settle on. With the engine mounted inverted the carbs are too low and upright they are a bit high. but a straight forward modification to the engine box adding an extra 2cms brings the top of the tank perfectly in line with the carburettors  centreline. A 1.5mm ply box for the tank fits between the firewall and F2   and this has added a fair bit of extra rigidity to the structure. With the tank high in the front end there is ample room below it for the  air tank and room either side for a pair of receiver battery right up against F1.

 

 

[Martin McIntosh]

The construction of yours is obviously totally different to mine and a  single cylinder engine can be put any way round I wish to align the tank. Have made a start on the cowl mould but will not hijack your thread and I shall put it under ` 77" Sea fury`

[Jon H]

Looks great Nick

 

If possible though, mount the air tank in/on the wing. It makes maintenance so much easier as the whole retract setup is self contained and you dont need the fuselage falling about all over the table when you are just trying to inspect the gear. It also saves a connection when assembling the model and is one less connection to leak ? 

[Nick Somerville]

Engine box all tidied up and the cowl rings in place. Jon generally recommends a twin tank set up for the v twins and I bought a pair of Slec tanks (16oz I think) but these proved just a little too wide so I have built the tank tray for a Dubro 24oz tank. I shall add an extra hole in the bung and set it up with two clunks feeding the twin carbs, a fill and drain pipe to the bottom of the tank going to a remote filler and a forward facing vent from the top of the tank terminating just behind the bottom of the cowl facing into the airflow. I did this on my P47, though only had one clunk for the single cylinder 180.

Jon, good tip re the air tank thank you.

[Ron Gray]

If you use an in line filler valve, such as the Dubro Kwik fill, then there’s no need for an additional hole. I’ve done that with some of my Laser multis and it works a treat.

[Andrew Calcutt]

Just watch the tail weight,got a YT and a black horse,both are tail heavy with lots of nose weight added makes them very heavy.Still my favourite aircraft as my Father used to work on them when he was in Fleet Air arm.

[Nick Somerville]

Thanks for the advice Andrew. My tail retract unit has been on a diet and has now been installed. There are two hinge points for the mechanism and both pivot rods are removable,  so if I get desperate I could remove it and replace with a fixed wheel. Having checked over some photos of my subject aircraft F-AZXL I was pleased to note that there is no arrestor hook and the associated housing hump was also omitted. That should save me a little aft weight.

 

 

It’s a good sign that I am getting to the end of the Belair laser cut parts, though I am short of some forward fuselage parts that need laminating to make up the cheeks around the exhaust exit area. The tail end is now ready for sheeting as both the tailwheel steering and rudder cables have been put in place. It was with some relief to find everything works as it should with no fowling, as the steering springs/cables slacken on retracting the tailwheel. 

I am heading up country to the Buckminster Fly In this weekend, with the plan to take my BMFA B test with my Wot4 XL. Fingers crossed I can get that monkey off my back and will then be able to fly my P47 that is just over 7.5kg . My club won’t allow me to fly it until I pass the test. Never been to Buckminster, but from the photos I can’t think of a nicer place to get her in the air at last.

 

 

[Martin McIntosh]

Weather permitting, you will love Buckminster Nick. Thinking about it for Sat. but I am not very mobile at the moment so the thought of carrying models out to the patch deters me. Best of luck with the `B`, it is really quite easy to fly. I got mine back in the 70`s but when I took up the hobby again in `97 the BMFA had lost all of my details so I did it again to satisfy my new club; worse than taking another driving test.

[Nick Somerville]

Buckminster certainly worth the trip. P47 finally had her maiden and B test passed to boot. What a great facility and flying field. The runway is HUGE.

The P47 flight was pretty hairy to begin with as even with full right aileron trim she still wanted to bank left a little, so holding that in and trying to sort the elevator trim left me rather busy keeping her flying in the breezy conditions. Landing was a dream though and in the wind I didn’t even bother with flaps. Tomorrow expecting lighter winds so will try again and hopefully have someone film for me.

[Jon H]

Good to hear the maiden was a success nick. One thing i suggest you check is your rudder trim as torque will yaw warbirds much more than sport models. Left yaw means left roll, so have a look at that. Dont be surprised if you have to fly it on rudder through turns to keep the track straight. Loops etc again do not be surprised if you are holding half your rudder deflection in to keep it on line. Today iw as flying my La7 and looping across the wind i needed near full right rudder through most of the loop. Its just they way the are so dont bother faffing with right thrust as that will create its own issues. 

[Martin McIntosh]

Well done with the `B` Nick. Due to the change in the weather forecast I decided not to go anyway. It was quite windy and very wet most of the time where I am.

[Tim Flyer]

Well done Nick, was great meeting you at Buckminster and seeing your very impressive P47 . I will be following this build with interest too. 

[Nick Somerville]

That’s most of the fuselage sheeted now, with just some pieces to do around the exhaust duct area. In fact there is quite a bit of shaping to do around there for which I shall need to really study my Sea Fury photos and book.

Servo rails added and carbon pushrods in place for elevator and tail retract. The plan shows these further aft, but with good pushrods with supports half way down the fuselage there was no reason not to get them as far forward as possible.

Meanwhile I have sandwiched some 1/8th balsa with a layer of carbon fibre inside and glass cloth outside and taped it over the tailwheel door area. This is a little oversized and placed 1 cms aft of the actual position. That way it should fit nicely once the aperture has been cut and the doors trimmed to drop in place.

[Nick Somerville]

While working around the tail end I realised I had glassed my rudder but omitted the balance tab. Something else to keep me out of mischief on a wet and windy day.

[Dale Bradly]

Nice work, keep it up!

[Nick Somerville]

 

Doors worked out well. Nice to cut out the bay and find the retract still there! Hopefully a little shirring  elastic  fixed between each door and the retract carriage should pull them shut as the wheel ascends. 

[Piers Acland]

Lovely job on the doors Nick.  Is the resin between the carbon fibre and the balsa sufficient to hold the profile before glassing or did you do it all in one step (carbon fibre resin plus glassing at the same time)? 

[Nick Somerville]

Yes Piers, all in one go. Light weight glass,1/8th balsa, carbon weave and glasscloth again. Used barely any resin to wet out and laid on waxed plastic sheet and plastic sheet again on top before taping it down tight. Super smooth surface this morning when peeling away the plastic and all light as a feather.

[Piers Acland]

Thanks for the info Nick

[Nick Somerville]

Have tried using elastic shirring to pull doors closed but despite trying a number of attachment placements I am unable to get this working. The carriage moves through an arc and most of the pull comes in the first part of the retraction. This pulls the doors too quickly and therefore the wheel nuts, although fairly flush, snag on the doors. If I loosen the elastic then there is insufficient travel in the last part of the carriage rotation to close them.

 

Would appreciate any suggestions on how else to actuate the doors.

 

[Jon H]

On my P39 i use sequenced servos and thin wire pushrods fed through a snake inner. I use some sequencers from hobbyking and although they are a faff to program they get it job done.

 

It works well as you can see in my ancient video, the only snag is the retract system on the model now uses 5 servos (4 for doors one air valve) and 2 sequencing units!

 

 

[Ace]

Could you not stretch the elastic across further inside the fuz so the retracted wheel only touches when nearing its fully retracted position, limiting the force and ensuring the wheel has cleared the doors so speed is not an issue. It would also allow the wheel to push the doors open if gravity hadn't as they wouldn't be under tension.

Will the doors stay far enough apart in flight when open not to foul the retracting wheel? 

[Nick Somerville]

I have left fiddling with the tailwheel doors for now and have done some work on the cowl retention. Matching top and bottom cowl rings were made and reinforced with 12mm ply blocks where the 4 x 5mm nylon allen hex head bolts will pass through.  As there is a break in the cowl ring on either side for the exhaust ports I have added a couple of strips of carbon cloth for rigidity and this has worked out rather well. 
 

The bolt fixings are positioned accordingly for the engine and should retain the cowl well enough even though not as evenly spread as one might wish. To aid lining up I have inset four sets of small but strong magnets. The nylon bolts will tighten into 5mm threaded inserts, though I need to work on a technique to get these to screw in straight as they have a tendency to cut their thread off centre. I shall keep practising on scrap ply until I get it right before committing to the model as it will be a PITA if I they go in squiffy.

 

 

 

 

[RottenRow]

Hi Nick,

Is there any specific reason for you to use nylon bolts to retain the cowl? As you say, if one of them goes in out of true it will be troublesome to remove. I presume your only access to the bolt heads will be through the front of the cowl, with the engine installed but prop. and spinner removed.

If you were to use steel socket-headed (allen) bolts then they would be less likely to jam in the threads. Also you could use a magnetised hex bit holder and extension to aid their insersion.

Alternatively, you could fit threaded studding into the firewall, have clearance holes in the cowl and fit nuts using a suitably sized socket and extension. That would make aligning the cowl easier.

I've had nylon bolts jam up in threads in the past and the heads have twisted off before the threaded part even attempted to move.

Brian.

[Nick Somerville]

Brian, thanks for posting your thoughts on the fixing. I had considered the nylon allen socket head bolts as I figured getting a long driver into the cowl (spinner off) would be fairly easy and also because they shouldn’t vibrate loose as per metal bolts.  Mind you perish the thought of one breaking in the thread ?. The stud idea could work well and nyloc nuts can then be used.