Viral lock down survival kit......Seagull Steen Super Skybolt assembly!

[Mike.K 60]

Being locked into our homes, means filling the time that we would otherwise be using out and about. For me, that means creation of yet more model planes....

With my long term Fly Baby scratch build now rapidly approaching the final stages, I`ve been looking for another project. Knowing the Seagull range of kits so well, lead me to look at their Skybolt. It follows the normal and typical Seagull kit assembly pattern. No surprises there. For those that don`t know the Skybolt, well it looks very much like a Pitts Special.

I expect to order the kit in around a months time. It won`t be sooner.....I`m still recovering from the cost of the Jungmeister build!

In the meantime, as a taster to what will be coming, here are some links to a review and a couple of Youtube videos.

Seagull Models Steen Super Skybolt 15cc ARF Preview Preview 4:13 Seagull Models Steen Skybolt ARF

Watch this thread for developments.

Mike

Edited April 9, 2020 by Mike.K
Corrections

[Mike.K 60]

Bought at one of the Club auctions a couple of years ago, this ASP 1.08 two stroke motor fitted with an Irvine silencer is in very low use condition and was discovered quite by accident when I raked through my engine stock. I forgot I had this very tidy and almost unused engine. OK, two stroke motors have gone out of fashion being noisy and dirty but it seems a shame not to put this engine into service. It would certainly be suitable for the proposed Skybolt kit. It would also save a few quid in the process. Nothing is set in stone so this engine could always be removed and a substitute 120FS installed in its place at a later date. If I put two differently positioned throttle pushrod tubes in the model when I build it, I then have an instant choice ready to go for either power plant. I`ve loads of spare engine mounts which could be drilled to pick up common blind nuts on the front bulkhead.

Now needed are a handful of Robs good used servos and another FrSky FASST receiver. These parts will be gatheredas soon as possible but obviously getting over to Avicraft at Bromley is currently an impossibility due to the virus travelling restrictions. I`ll have to call Rob and see if he has some and can post them to me.

Please note I`m always in the market for good problem free used or new four stroke .91>180 motors and also used good condition Futaba or Hi-tek standard sized servos. Give me a call or PM me if you have this type of gear to dispose of.

Mike K

Edited April 12, 2020 by Mike.K

[Mike.K 60]

About change!

The Seagull Zlin Z50 has had its SC120FS snatched for the imminent assembly of the Seagull Skybolt. The above ASP 1.08 two stroke which hadn`t been installed in anything since I bought it at one of our Club auctions a couple of years ago, now sits in the Zlin. Its an economical way to gain the engine I wanted for the Skybolt with no additional costs involved. Images depict what occurred.

Rob now has the kit ordered from Perkins. He now has My Hermes delivering at what he says are excellent prices. He tells me he sent out a kit weighing 8Kg to a customer on two day delivery for just £6.50. Had he taken it to the Post Office, it would have cost in the region of £30! Rob is still open for processing mail order deliveries whilst the Covid lockdown is still in operation.

Mike

[Mike.K 60]

The Skybolt kit was collected from Rob on Tuesday. Together with a few other bits and pieces, Rob dropped the pile outside the shop door and I paid for it using his card reader which he placed on the shop door threshold......... I`ve never had to go on my hands and knees to pay or pray for anything previously. I think he just wanted to watch me struggle to get up off my knees........ Another case of daylight  Robbery with a smile as our esteemed friend and model shop proprietor helps himself to the contents of your piggy bank! A lovely bloke is our Rob.

The kit is not a big one. The wingspan is just 61" with a quoted weight of 9.3Lbs (4.2Kg) Images below show the kit being unpacked and the component parts contained in the box. Its another quick assembly model and once again represents great value for money. The model generally sells for around £297 from most leading internet sales sites. As  usual, a motor, servos, receiver, batteries etc will be needed at additional cost. If I were to build a similar model from a plan and source parts as required, costs of such a build could easily double. My equivalent scratch built model would no doubt be heavier, less accurate and be less likely to fly as well as a production kit equivalent. It would also take at least ten times the hourage to construct. If you haven`t the time or inclination to scratch build, these kits give you a fantastic looking model for minimal cost. I like them despite the occasional problems one has to overcome.

This particular kit is a fast builder although assembly is probably the better term. Prior to commencing the assembly, I`d found a nice review on the kit from an American, Geoff Barber. Geoff had catalogued his assembly photographically so using his review and an online copy of the builders manual, I knew what issues I might find before the kit was even with me. Several small issues materialised on Geoffs build. Firstly the detail on landing gear fit up is inaccurate in the manual. To allow axles and wheels to be fitted, two small slots have to be cut in the wheel spats. That done, assembly progresses fairly normally.

I quickly found another issue with the landing gear. The painted dural two part leg components were cold bent to form the core shape onto which the wheels, spats and axles are bolted. Bending sheet dural or indeed any metal induces work hardening of the material which makes it strong but brittle when subjected to stress reversals ie vibration or in this case landing impact shock loading. The situation with the two sections of dural wasn`t helped by having two cuts in the metal to remove unnecessary excess material. The cuts were at 90 degrees to each other and formed a massive and wholly unacceptable potential metal fatigue fail point. The remedy was simple. Taking a round 1/8" needle file, I worked down into the 90 degree joint removing some paint in the process. As expected I found cracks propagating at 45 degrees away from the 90 degree cut angle. I continued to file until I`d hit the bottom of the crack and radiused the filed metal to fair out the profile. In the aircraft industry, cracks are often found in aluminium structure. A standard and accepted form of crack stopping is to drill a 1/8" hole at the end of the crack which then acts as a crack arrester. The same principle was therefore applied to the two cracks found on this Skybolt landing gear. I`ve left my intrusive surgery un-painted in order that I can monitor any further potential crack precipitation in the future.

The SC120FS motor I`m fitting is a large unit and I found the front motor mount bulkhead to be slightly short height wise. In addition, the engine mount bolt holes where inappropriately spaced to accept the engine mount hole spacings. I`ve deliberately set the engine well forward on its mount to allow a decent amount of fiddle space to the rear of the engine. By doing this, I have more space to work fuel pipes and the throttle control clevis and rod becomes more accessible. I elected to make a new 10mm thick bulkhead from laminated high density Birch plywood and to chop off the old bulkhead completely. The new bulkhead now sits 15mm further aft than the original. New triangulation pieces support the new bulkhead and tie it in well with the original structure. The existing fuselage F2 area and the new bulkhead have been coated in epoxy as fuel proofing and to improve appearance, the bare wood around F1 and F2 have been covered in chrome effect Oracover film. In doing so, my covering iron blew up but its ok again now!

Another more major problem also came to light. The model has a belly pan of ply and balsa below the bottom wing. Taking the component I tried to fit it. No go. Seagull made a right mess of this bit. Not only were two end bulkheads put on the wrong end of a cruciform structure, the top sheeting had also been glued on the wrong way around. I had to cut the complete unit apart, re-profile the structure, fit the bulkheads in the right place having adjusted the slant of one of them then had to re-sheet the re-work. I also found no allowance had been made to allow the bottom wing to be removed once the belly pan had been fitted. That rework took six hours to fathom. Not good at all. It is such a shame that Seagull drop so many guffs. The majority of their productions are good but there is always and without exception some difficulties to overcome whatever kit of theirs that you build. This is probably the worst example of poor detail execution I`ve ever seen on a production kit to date........Not all kits have such fundamental cock ups included in the price. One doesn`t expect to buy a kit and then have to sort out manufacturing details. In perspective, Seagull kits are 99% good. The other 1% does `yer head in!

Here then are images of the Skybolt assembly as it nears completion. More soon.

Mike

 

M

[Mike.K 60]

After just ten days of moderate effort, the Skybolt is 99% finished with only a 240mm long flexi exhaust pipe and the silencer still to be fitted. Just Engines will be sending the flexi pipe in the post shortly together with an external fixing bracket kit. The cost for those parts comes out not far short of £40 but avoids the need to mount the silencer within the cowl. The silencer will fit centrally under the fuselage with mountings to hold it firmly under the central parts of the landing gear. Maintenance will be a lot easier than an internally cowl mounted silencer as well as getting exhaust heat away from the inside of the cowl.

I`ve added eight lengths of light weight 2mm round rod as braces for the fin and tailplane. Example videos of this Seagull Skybolt model show the thinly sectioned tailplane to deflect badly when the engine is at idle or when taxiing. I could see this leading to an eventual structural failure so copied the reinforcement detail from the full size aircraft. The rods are so light that they defy weighing on my electronic weight scale. Any extra weight accumulated at the tail by incorporating the brace struts is well offset as I`ve taken the mild steel elevator and rudder push rods out of the model, again in favour of using 2mm carbon rod as replacements. Three lengths of mild steel rod equates to nearly three and a half ounces of tail end weight with the replacement carbon rods probably only weighing half an ounce by comparison.

The 2600NiMh receiver and servo battery has been mounted well aft within the fuselage with some allowance being made for the still to arrive exhaust flexi pipe. The battery is mounted with cable ties upon a 1.5mm ply plate located directly under the front cockpit floor. An easy C of G balance was achieved using the battery as portable ballast to get the C of G as per the makers suggestion. This is 120mm aft of the leading edge of the top wing in the central cabane area. Other modellers report that the position appears good and doesn`t require much if any alteration.

The final part of this model assembly required the cowl to be fitted. Annoyingly, the cowl would not fit over the F2 bulkhead as shown in the makers manual. Short of stripping off covering and sanding external balsa sheet until the cowl fitted, I elected to mount six softwood timber blocks around the periphery of the bulkhead. I set the blocks inwards by 1/16" from the edges of F2 to allow the cowl to sit flush with the extremities of that F2 bulkhead. The finished modification uses six self tapping screws to hold the cowl to the blocks and is visually fine. What was not so good was the alignment of the covering and trim on the port side of the model cowl. Images here show how badly the alignment was and how I got over the issue using covering from my stock to lift the black trim up by nearly 3/8" before adding replacement red pin striping. These kit makers really do need to take more care with their products.

Apart from issues with the landing gear, the cowl trim mis-alignment and the belly pan, the model was simple and straightforward to assemble. Its a great shame that the mentioned issues can cause an otherwise sensible construction to become marred by bad detailing and lack of care at the factory. Whilst the cost of the kit is around £275 which isn`t a huge amount for a pre-covered model, one does at least hope that all the parts will fit together in a problem free manner. I`ve previously written to Seagull via J Perkins but no reply has been received. It leaves you wondering if Seagull really care about the issues that crop up in their kits. Somehow, I think not! That is a bit of a shame because their kits would not just be good but they would become perfect....

The final dry flying weight is 10Lb/4.5Kg complete with a slightly larger fuel tank and a 120FS fitted in place of the suggested 90FS. Weights in both cases are fractionally more than with a 90FS and the standard and rather small fuel tank. The final weight is about 0.6Lb more than the manufacturers guide weight in the build manual. I`ve never got any Seagull build weight down to what is quoted so the extra weight comes as no surprise.

My overall rating for this model would be 4 out of 5 stars. Any issues encountered are relatively easily sorted but a little frustrating to have to correct.

Finally the pilot came in for a re-work. As the model replicates an American aircraft (crashed in an inverted spin) which was given a Batman paint job, I decided to give the pilot a Batman appearance. Sadly I couldn`t add bat ears as there was insufficient clearance between his head and the canopy. The impression is what counts so Batman now has red eyes and grey lips which give him a somewhat goulish appearance. My granddaughter loves him!

So another model joins the other fourteen of so models in the garage and awaits test flights. More on that in due course.

Mike

[Emma 47]

Thanks for another interesting read Mike. Looking forward to see what's next on your workbench!

Em x

[Mike.K 60]

Thanks, Em.

Finally, I got the exhaust sorted. Quite straight forward in the end. ASP/SC 120-180 FS engines all share a common exhaust header pipe and screw on silencer with 14mm threads. I wanted to mount the silencer outside of the cowl and needed compatible after market parts. Just Engines sourced me a 14mm female to female coupler, a silencer mounting bracket and 140mm length of suitable flexi pipe. Those parts are not particularly cheap though at around £40 plus post and VAT. That said, the components are of exceptionally high quality and do the job without drama. You either pay the money to get a well engineered result or you struggle with sub-standard parts and an unreliable result. I`m glad I spent the money to finish the build off to a more than acceptable standard. Images below.

The Skybolt is now completely finished. The C of G was easily achieved and everything works as it should. Now the model needs to be flown. I must have a word with Rob Newman once the lockdown is eased. When we can handle each others models again, there is no reason why Rob and I shouldn`t buzz off to the Falcon Group site for some test flights in a large field. As I have several other models that need test flights, it would be good to have Rob around for the trial flights.

More news on this model once it has received its baptism of fire..

Mike