DB Sport 60"Bi-stormer build.

[Mike.K 60]

My latest build.

This is the 60" Bi-stormer from the late David Boddingtons` drawing board. Essentially the model is a Barnstormer with two wings. The design is about fifty years old and is much loved as a medium sized, soft floater for balmy summer evening flying. Images below show progress made to date. A 72" version is also available but is a little too big for my storage and transport convenience. Build costs also escalate the bigger a model is. I found that out to my cost during the Midwest Extra build.

I bought the DB Sport and Scale kit last week direct from the makers in Wales. The kit is very much a "short" production type at £110 delivered. Delivery/production took about a week. DB Sport  has changed hands several times since the late David Boddington sold it on. The kit is not really a true kit when compared to modern offerings. Much of it is "missing". You get a plan, dural landing gear and cabane struts, pre-cut sheet balsa fuselage sides, a few ply bulkheads, two wing rib packs and a few other assorted air-frame parts. It is all very basic indeed but what do you expect for the money after the producer has made some profit?

The traditional construction of the model is sticks, twigs, sheet and the odd bit of ply. Building the kit is rather like constructing a Keil Craft Super 60. To complete the model it is necessary to purchase wing sheeting, leading and trailing edge material and balsa square section for the fuselage longitudinal members together with control horns and snakes, wheels, collects, coverings, etc. By the time you have all the parts together, you are looking at about £240 as a finished model. Price wise, a pre-covered ARTF makes better financial sense but I wanted a nice model to scratch (or nearly scratch) build so obtaining a near ready to fly model wasn`t an issue or was value for money much of a consideration. Perhaps price wise as a kit, its probable value is little more than £70. The extra £40 can be regarded as the makers slender profit for getting it into a box and flinging it in the post! This type of cottage industry produced kit will always be quirky and relatively basic. It is what it is and it ain`t what it ain`t! So you accept what it is and get on with the build.

The build is quick and easy once you have rounded up all the extra required timber scantlings. The majority of construction has been done with Screwfix CA adhesive or Toolstation 4 minute epoxy. Both products are as cheap as it gets and have become my favoured adhesives. I don`t use much alaphatic white glue but when I do, I`ve used Gorilla Glue which seems to set up quickly and is water resistant.

I usually do between eight and ten hours building each day. The fuselage and tail feathers have therefore taken about seventy hours work. It is not so much the volume building that takes the time but the attention to detail. That said the experience of building this model to date is very pleasing. It is a pretty little bi-plane which is known to fly extremely well. I now have to build the wings and cover the whole model. I envisage about another one hundred hours needed for that. If all goes well, the model should be capable of flying within the next three weeks subject to all continuing to progress well. Elevators and rudder are a little larger than standard. Many builders have said the larger elevators help when it comes to three pointing the model when landing. The top wing will loose its dihedral in favour of a flat wing. Ailerons are also described as a little non reactive so I expect to increase size slightly and perhaps to include ailerons on both wings. Advice will be sought from Rob Newman today when I go over to Bromley for further building supplies.

Colour scheme? Not really thought about yet but the model has strong likenesses to the Stearman. I do quite fancy a silver machine with white and red checker and RAF markings. Pre-war the University Air Squadron operated Tiger Moths and Hawker bi-planes at airshows of the period. Essentially those guys were the forerunners of the Red Arrows. If you know the Shuttleworth Tiger Moth, then you will have some idea of what I have in mind.

Power will come from the auction sourced £4 SC.61 which is now in fine order having had its carburetor cleaned out and a missing needle valve spring replaced. Compression is excellent and it is quite clear this motor hasn`t seen much action. It is the right size and "shape" for this model but if power is marginal, then I have a brand new ASP.75 which has identical external sized components to the SC.61. Both motors were built in the same Chinese factory but are just badge engineered as an SC or an ASP.

The dead Dynam Hurricane pilot has been resuscitated and lives to fight another day in this model. Harry Hawker flies again! The remains of his air-frame have donated a bullet-proof windshield which fits the top deck to perfection.

More on this model as it progresses.

Mike.

Edited June 13, 2019 by Mike.K
Spelling corrections.

[Pilot Ben 28]

That looks very smart Mike! Do you know yet what the rough AUW could be? 

[Mike.K 60]

Ask me in a week, Ben!

Difficult to tell weight yet as the wings are still to be made. The fuselage seems light enough even with the three MG996 metal gear standard servos installed.

I nipped over to Robs this morning to collect the usual nick-nacks needed ie control horns, engine mount, poppers for press fit inter-plane struts, ball links for aileron push rods and a nice second hand ali spinner. That has rubbed up very nicely. The model is a great traditional build with loads of stringers and a fair amount of block work to shape. Its very rewarding to see it all coming together so quickly. I have a good feeling about this model and I`m confident it will fly very nicely. Emma and I joked that this model is a "James model". As we know, he loves the vintage stuff. I took a shine to his Fly-Baby bi-plane some time back. I`ve not yet found a plan for one yet but would love to build one. I found a Balsa USA kit for $365 plus shipping, import VAT and extra delivery charges this end. Obviously this was impossible to justify, hence the building of this Bi-stormer at a rather less dramatic price.

More on this build when I have some further progress made and images taken.

Mike

[Mike.K 60]

It progresses well. Wings built now and covering in progress. The build time has stretched a bit due to my Father being laid up in East Surrey Hospital and having to drive down there several times a day. I see I started construction of this Bi-stormer about five weeks ago so even those commitments the build hasn`t been that slow. Images here show where I am currently with this model. Can`t wait to fly it!!

More in due course.

The next build is  JP Panic which I`m due to collect from Rob shortly.

Mike

[Pilot Ben 28]

Looking great! It's also nice to see a good helping of fuel proofing/lacquer/epoxy at the front. Far too many ARTF manufacturers and even builders rely solely on the covering for fuel proofing, and it's always a shame to see the covering peel back to reveal a soggy and crumbly firewall! 

I also look forward to seeing the panic build; they really are amazing models, and I'm interested to see how they come together construction wise.

Oh, and I really like the chosen colour scheme! It gives a different feel than the drab schemes adorning many builds, but yet still manages to capture that retro feel

 

[Mike.K 60]

Thank you for your kind comments, Dear Boy. Nice to have some encouragement even though I`m only sixty one!

With apologies for the late evening image quality and the total chaos shown in the images, here are a few more shots of the now rapidly completing build. I only took these ten minutes ago having spent the day covering the wings. More bright orange trim is due to aid my now degenerating eye sight...

To answer your AUW question Ben, with just the receiver, 2600NiMh power pack, piano control wires/clevises and light weight inter-plane struts still to be added, the current kite weight is 9.1Lbs/4.14Kg. This figure includes five metal gear servos which account for a monstrous 10oz weight penalty. Fitting nylon gear servos would knock about 5oz off the total. Yes, it is a tad heavier than I`d like but I`m known for building flying bricks with high landing speeds. Shown in the images is the £4 auction sourced, used but in great apparent condition, SC60. If it runs well, it will be a total bargain.

All the above done to the strains of Mark Knopfler on his latest tour. His band just get better and better. I saw him at the Albert Hall with one of my daughters about ten years ago and we came away rocking. Since then, all the model building has been done with his magic belting out constantly. He hand picks the Worlds finest players and it shows. I never tire of his riffs and guitar licks and the long hours of building go faster as a result.Mix - Mark Knopfler Done With Bonaparte 14 juillet 2019 St Julien En Genevois YouTube •

I`m due to collect the Panic kit from Rob on Tuesday. This gives me the chance to finish the Bi-stormer and grab any further parts I may need at the same time. For those that didn`t see the June 2019 edition of RCM&E magazine, Jim Beagley has his review article included on a Panic build. This is the JP kit produced and distributed by Perkins in India with permission from Rob. This was what finally pushed me to get hold of one. Mine will have a brand new and unused SC.75 two stroke which came to me for £26 via eBay. It seemed a good punt for the money and needs a flying home. The SC 60 and 75 share the same crank case castings and dimensions so this makes inter-changeability a doddle.

I recently heard that SC/ASP motors were no longer going to be produced. Can anyone confirm?

That`s it for tonight.

Mike

Edited July 20, 2019 by Mike.K
Typo corrections

[Pilot Ben 28]

Well. The ASP factory has indeed closed down, and will not be reopened. That said, I believe (?) that SC and Evolution engines will continue to be made in other factories, however their supply will obviously be affected.

 

4.14kg does seem quite a weight, however this isn't that small of a model, and looking at the extremely solid construction, I wouldn't say that 4kg seems too unreasonable. Going with metal geared servos will pay off, Mike. I run metal gears in nearly all of my models, partially due to the fact I prefer the slightly more robust servos in the air, but mainly because I'm fed up of stripping gears when I knock a control surface!

Mark Knopfler is indeed one of the greats, and indeed his new tour is very impressive with regards to band members and himself! Personally I'm just about to finish learning the first solo in Sultans of Swing, and I'm excited to move on to the second!

[Mike.K 60]

A few more images of the finished Bi-stormer. Note my originally upright mounted motor which caused a few issues with the throttle rod which included acute ends at either end. Control wise, it really didn`t make the required grade so I ripped the motor and mount out again and butchered the starboard cowl cheek to allow the motor to be turned by about sixty degrees. This allowed a straight push/pull from servo to throttle arm along the tank floor. The modified installation now functions in a much improved fashion compared to my first attempt. I didn`t want to hack the model around but push became shove and I`m glad I bit the bullet.

Whilst my modification is now totally functional rather than aesthetically pleasing, functionality overrides prettiness. I`ve left the top of the cockpit combing open and the starboard cowl cheek has been removed completely. Access to engine mount bolts and the throttle control rod is almost as good as not having a cowl at all. Viewed from the port side, no visual changes are evident. Viewed from the starboard side, whilst the cheek has gone, the effect is of an open and easily serviceable engine installation. Viewed from the front, the upright and chunky cylinder crank case no longer dominates. Twisting the engine to semi side winder configuration actually improves appearance in my opinion. It also lowers the carb spray bar which should help maintain reliable fuel flow.

Now finished, the Bi-stormer is ready to fly once I`ve gained some experience on a newly built Panic.

The build as a project is for the building enthusiast. I`d estimate I probably spent around the usual 300hrs from start to finish. Was it worth buying the short kit? The short answer is an emphatic negative. I could have saved about £20 cutting out my own wing ribs. (A cut out rib using a template usually only takes me about 3 or 4 minutes a piece. The kit contained pre-cut front to mid section balsa sheet sides. They accounted for little more than a fiver. The laser cut bulkhead were useful but not an essential item. The pre-bent strip ali cabane struts and landing gear were the best features of the so called short kit. Nicely produced, accurate and avoided the need to bend material ones self. Sheet and strip balsa accounted for about another £70. The lovely silver covering came from Hobby King and I price that at about £8. It really is brilliant value for money and is a top class material. Around £23 was paid for a 600mm x 2m roll of orange 021 fluorescent Oracover for the trim. I used every scrap of that roll of covering. The pre-owned motor cost £4, the tank came from stock and five Tower Pro digital servos came for £3.50 each, delivered from China. The pilot came from the smashed Dynam Hurricane. Wing fastenings are 6mm nylon sheer bolts with threaded base mounts. All done and dusted, the model probably cost me £250 to bring to flying condition. I`m certainly pleased with the finished article. All that now remains is to fly the thing.

Colour changes in the attached images are due to some images being taken under florescent light, whilst others were taken in natural daylight. Believe me, the orange is all the same colour!

Mike

Edited August 12, 2019 by Mike.K
Typo corrections.