Yet another Seagull build....Bucker Jungmeister 65".

[Mike.K 60]

Here we go again....I need another kite to build!

With Emma`s kind help at Avicraft, we looked at the Seagull Bucker Jungmeister kit listing online. It would make a great stable-mate for my Seagull produced Stearman, Fly Baby, Sparrow Hawk and Gypsy Moth. The Jungmeister is presently in transit from Vietnam and expected at J Perkins on or around 20th February 2020. That should give my ruptured wallet time to recover from my Christmas and New Year spending sprees.

In the meantime, I`m on the hunt for a good used OS1.20 FS or similar spec motor. There is a pumped version listed on eBay so I`ll have a punt on that. A spare receiver sits here in its box unallocated and a few servos are also to hand. I`ll collect a few more good used examples from Rob in due course.  As is now my habit with these somewhat heavy tailed Seagull kits, I`ll also be swapping out the heavy mild steel push rod wires in favour of 2mm carbon rods. A couple of saved ounces at the tail end often saves six ounces at the nose with a total weight save of about half a pound. Servos will also come as far forward as possible to help with weight and balance issues. Using this method, I managed to get the Gypsy Moth to balance correctly straight from the box and without any dead weight ballast being placed in the nose. That was totally unexpected and I suspect I probably have the lightest built Seagull Gypsy Moth around. Not many people would go to the bother of moving servos or swapping wire pushrods. The small effort in the modification involved certainly pays you back very quickly. Its total joy to have a model C of G in the correct place without much effort or additional ballast.

The Seagull Jungmeister manual states the "air-frame" weight to be 11Lbs. Bearing in mind all my previous Seagull kits have always exceeded the stated weights by about a pound, I`d expect the Jungmeister to also exceed the manufacturers guide weight by a similar figure. How I wish makers would clearly state the finished airframe weight only and also give an example of that same air frame once fitted with typical servos, battery and motor. This of course would be a highly variable figure dependent on what equipment a particular builder installs but some guide figure would be helpful. The complete finished all up weight figure affects all of us who fly within our local Flight Restriction Zone where the maximum dry weight of a model must not exceed 15.7Lbs/7Kg. Building a model with a final weight in excess of that 7Kg obviously makes it an illegal flyer within an FRZ. Best then to only choose kits or scratch built models that have a good chance of completing at below the 7Kg figure.

Seagull produce three different covering colour schemes for differing World markets. One is of a yellow Swiss Airforce with typical white cross on red background markings. The second colour scheme is for an American aircraft in white with red trim. That is very similar to my white and red Stearman. The third option is clearly for the European market and that is the one which Perkins say would be the one that would arrive in their next consignment. If I wanted either of the two other colour schemes, the order would have to be processed as a "special" and delivery would probably take several months. This third colour scheme depicts an aircraft flown to winning place in the 1936 Olympic Games aerobatic championship flown by the outstanding Romanian pilot, Alex Panapa. Following his successful win, the aircraft was transported across the Atlantic UNDER a German Zeppelin airship! Papana went on to campaign the Jungmeister across the US for many years until it was severely damaged in a landing accident. It appears the aircraft was landed upon by another aircraft! Left for scrap, the air frame sat against a fence for years before it was recognised for its historical significance. Restoration followed before it was eventually placed in a museum. Papana in later years suffered from depression leading to him abandon his car in the desert then wandering seventeen miles from the vehicle before committing suicide by taking a poisonous substance. A very sad end to a World acclaimed pilot. My model will therefore be a Papana example and will come in a white base colour scheme overlaid with silver at the front of the fuselage, red and white checker on the tops of the wings, red strips on the underside and prominent Olympic five ring logo on the tail fin and rudder. I`d quite like to have seen a German military version with black crosses and the dreaded Swastika political symbol on the rudder. I could strip off all the pre-applied Ultra cover but I`ve no plans to do that....

Here then is a video of an electrified version of the Jungmeister and also a PDF of the build manual. I look forward to the arrival of the kit and will post here again as I begin assembly.

Flying my Electric Powered Seagull Bücker Jungmeister ARF

Jungmeister PDF

Mike

 

[Mike.K 60]

A small update on the forthcoming Jungmeister kit assembly. Obviously I`ve a while to wait before the kit arrives in the UK, so my thrust has been to secure a suitable power plant for the project.

Trawling eBay found a brand new and unused RCV 130CD four stroke glow engine. This unusual engine features a geared rotary cylinder valve arrangement rather than the traditional poppet valves found in conventional engines. Martin W has several engines of this type in various sizes and very good they are too. Bidding for this listed YS130 ended on Saturday evening. The bids had topped £96 up to the last ten seconds of the finish of the auction. I hoped that my bid of £162 would secure me the engine being pinged off within the last eight seconds. I felt confident.....but my hopes were dashed when an obvious automatic bid from another player smashed my dream to dust at £188! We can`t win them all!!

Having lost this auction, I had a second target to shoot at. A "buy it now" listing advertised an elderly, pumped, four stroke Yamada YS140FZ in used condition. It was of slightly grubby appearance, black rocker cover paint a little worn and described as having good compression and as an easy starter. No exhaust is present although the motor was in an original box, with a users manual, needle valve and a couple of other spare ancillary parts. Before committing to buy, I`d checked with Probuild in Wimbourne that all spares parts for this motor were easily available. No problem in that respect. I made a £120 offer to the engine seller which was accepted. An eBay notification this afternoon confirms the engine is now in the post to me and that it should arrive on Friday. I`ve taken a bit of a risk buying this relatively low priced engine unseen. If it is a good one, it will be a cheap answer to powering the Jungmeister. If it turns out to be a dog, I`ll have to deal with its issues as required. I think it no bad idea to overhaul the pump diaphragm, gaskets, springs and any other worn parts as a matter of course. The motor can be bench run before being test flown to establish reliability on one of my Ultra Sticks. It can then be transferred to the Jungmeister if proven satisfactory.

Now I need to acquire some suitable servos. Please contact me if you have any good standard size servos you wish to sell.

More news and more images in due course.

Mike

 

[Mike.K 60]

Well here are images of the recently acquired YS pumped 140 motor.

It`s a real belter of an engine for the money. It reminds me of the 6.75 litre engine in an old Bentley I owned many years ago! I miss that car if only for its incredibly solid engineering. I don`t miss its fuel consumption. It was every bit as heavy on fuel as the Jaguar V12 XJS I also ran for a while. The Yamada built YS140 is quite stunning and the motor, although as yet untested, is nailed to the front of one of my Ultra Stick flying test beds for familiarization and air tests. It really is quite a chunk of proper Japanese model engineering. It has a fuel regulator and also a diaphragm fuel delivery system which pressurizes the fuel tank via a take off nipple located on the motor back plate. Yes, the motor does require 16-20% nitro methane with a high oil content. Advice from Rob and also Model Technics advises use of the MT BEKRA product which is somewhat more costly than my standard use, 10% MT Contest fuel. Powerful engines require higher calorific fuel content. It is the price to be paid for using this type of motor.....My wonderful Bentley only ran properly on 5 Star leaded fuel so again there are similarities!

Pro Build have supplied the exhaust header pipe and the muffler. That does seem rather on the small side as is the exhaust exit pipe. If this motor is overly vocal, then I`ll have to fit a larger canister. Typical prop sizes are 16x10 or 16x12. More news on this engine and the Seagull Jungmeister in due course.

In the meantime, I`ve rescheduled kit delivery for mid March which gives me the time and finances to complete the Fly Baby bipe build.

Mike.

[Mike.K 60]

The Jungmeister kit is now with me. I`m pleased about that as it gives me another project to do whilst self isolating during the virus pandemic. A mass of images of the assembly can be found at the foot of his posting.

I`ve been working away on the Fly Baby bipe but its been hard work and I felt I could do with a break from it. Scratch building constantly requires a degree of "prototyping" which can be mentally draining after several repeated months of such activities. With the arrival of the Jungmeister ARTF kit, the majority of the hard work has been done for you so brain drain is reduced and mental application is less. The kit is again quick to build compared with a scratcher which probably takes at least fifty times the time input compared to a kit.

 A Seagull kit is incredible value for money coming as core prime components which are built and covered at the factory. A mass of completing goodies are included in the kit to save you dashing about attempting to round up the necessary completion parts. Its all in the box less power unit, servos, battery and radio receiver. The kit cost £310 with a bit of discount applied to the retail price by Rob at Avicraft. Comparing the Jungmeister kit cost with my scratch built Fly Baby, value for money, the Jungmeister wins by a mile. The scratch built Fly Baby has probably cost me twice the price to build with ten times the effort!

The above sums up the good arguments for kit building but what are the bad points, if any? The Seagull kits are not always perfect but neither are many other kits offered on the market.  Lack of detail application and  quality control at design stage is often the problem. I often ask the question. Do manufacturers flight test their models after they build a prototype? Sometimes it is quite obvious they don`t, otherwise kits would have had all the bugs ironed out of it before being put out on the Worlds market place. Build manuals can often be loaded with indistinct low image pixel images, are frequently unclear, are poorly produced and can cause an otherwise easy assembly to stall badly. Foreign kit makers really do need to buck up their ideas in this respect. Thats not the worst of it though. The most frustration comes from inaccurate prime point dimensions and information, silly CofG positions, and lack of general clarity. An example of this occurred when I came to installation of the motor in the Jungmeister. The manual gave a dimension which was 30mm adrift and messed up my initial installation. I`ve worked around the issue but it caused a lot of extra work. I know that Seagull can do produce some decent kits from their range which do build nicely. My other Seagull models, namely the monoplane Fly Baby and the Gypsy Moth were perfect in all respects. By comparison, the Stearman kit was a nightmare with parts missing from the kit, an over-weight tail-plane, incorrect CofG position together with difficulties of attaining a sensible and achievable weight and balance requirement. Some of the Seagull kits do indeed have an unexpected sting in the tail that can take time, effort and additional expense to sort out, not to mention creating massive frustration as you desperately try to find a way to dig yourself out of a very big hole! Just one more thing to mention.....

Seagull are very liberal with glue especially when it comes to installing blind nuts. They get the stuff everywhere especially in the threads. This can cause bolts to seize solid in the fastener which can mean having to dig into the model with a scalpel and remove the offending parts before restoring damaged structure and fitting a new nut. NOTE THIS POINT WELL. Be aware of this possible issue and make sure each and every bolt you install into a blind nut is satisfactory. Use a little oil on the bolt having filed a lead on the bolt to reduce any possibility of seizure. Bolt seizure takes no prisoners!

Its not all bad though. As disappointing and frustrating as any negative aspects of ARFT kit building in general is concerned, there are quite a lot of plus points to be pleased about which more than offset a few painful experiences along the way. Whatever grief might have been suffered sorting out the bad bits, the great thing about a typical Seagull kit is that 95% of the experience is good. Its certainly a lot easier than building a complicated scale model from scratch. Once one of these kits becomes a finished job, the overall "feel good" factor and general completed impression makes for a very pleasing result in probably less than fifty hours spent on assembly and detailed fettling. You can end up with a very plausible model and everyone thinks you are a Master Model Builder! Compare that to the five hundred hours or so that I`ve spent to date constructing the Fly Baby bipe from sheets of balsa and slabs of plywood!...Double the cost and getting on for ten times the man hours spent hacking and chopping materials into something that resembles a model!!! A kit built model is likely to weigh less than a comparative self built model and will probably "fly well straight from the box". Getting a scratch built model to fly anything like as well initially is likely to be a rather more hit or miss experience......

The Jungmeister is now nearly complete after just ten days of working on it for an average of about eight hours a day. All I now have to do is rig the flying wires, re-check the CoG and install the battery to achieve correct weight and balance. Then it is finished and can join the rest of my collection in the garage. i`ve enjoyed the assembly even though I`ve had a few issues along the way. If we are ever let out flying again, I`m very much looking forward to seeing this model in the air.

Right, a few costings on getting this model complete and ready to fly.

Seagull SEA212 kit from Rob at Avicraft. £310

Large Kavan fuel tank.                                 £ 10

Toolstation super glue & 5 min epoxy.      £ 15

Extra nuts, bolts,washers etc.                     £   5

Used servos from Rob.                                 £ 25

FrSky FASST Rx, Rapid Rc                            £ 25

Used Yamada YS140FS engine,ebay.         £ 120

New exhaust system. Just Engines.           £  30

Fuel pipe and filters.                                       £   7

Propeller. 16 x 10.                                           £ 10

Exhaust extension.                                          £   3

2mm carbon fibre push rods.                         £  15

Extra clevises and couplers.                           £    6

100Lb breaking strain uprated flying wires. £   5

2600NiMh radio battery.                                  £    9

Total cost of build.                                            £595.....Ouch!

 

Now the crunch factor. Model weight. This Jungmeister has finished at a weight of exactly 13Lb. Not exactly light and two pounds heavier than the makers stated figure on the box. I`ve done little if any weight increasing modifications other than to fit a slightly larger than recommended engine. That extra weight to all intents and purposes could be considered negligible. It is at the front end of the model and possibly helped achieve an easily achieved and sensible C of G position. The NiMh battery sits just forward of the servos. No issue with that.

Keeping the weight down is frequently an issue with these ARTF (Almost Ready To Fly) kits. The majority of construction is from thin ply which comes in 8x4 sheets. This is popular with manufacturers as almost a complete kit can be laser cut in one go on the cutter bed. ie only one operator action which means that he could probably operate five laser machines at the same time. Compare that with the same operator having to constantly load a cutter bed with 150mm wide by 1000mm long strips of sheet balsa. Production time and effort would obviously increase dramatically. So 8x4 ply is the preferred makers option which is fine for him but not so good for the modeller. Ply models will come out heavier than a balsa equivalent. Hence the high weights which we constantly seem to experience with these kit models.The wing load on this model is quite high due to the 13Lb finished weight. The following calculation shows that 13Lb equals 208oz. The wing area is some 8.6 square feet of useful lifting potential. 208oz divided by 8.6 square feet gives a wing loading of 24.2oz per square foot of area which is quite a high figure and will make the model have to fly quickly to stay in the air for normal flying activities. The fun will start on landing circuits and approaches. The high drag factor from two wings, the massive fuselage frontal area together with flying wire drag mean the power will have to be kept on to overcome that drag and speed will have to be kept up to stop the model falling out of the sky! So no tight turns at slow speed with landings being achieved at highish approach speeds. Power has to be kept on to the last moment! This model will take practice and experience to master and that assumes it will survive the first few flights! I`ve just had a long discussion about this very matter with my great friend, Pete Ward at the Falcon Model Flying Group. Pete and I have similar passions for bi-plane models and also share similar thought processes. Pete has offered to help me commission this Jungmeister and the other Seagull models now in my rapidly expanding collection. That is damned decent of him. Challenging this hobby can certainly be.

That is about it now for this Jungmeister. More news once we have attempted the trial flights.

Take a look at the assembly images now. As always, comments are appreciated.

Mike

 

 

[Mike.K 60]

A second opinion and a well balanced review from Australia in this link. The Jungmeister had been converted to electric power, weighs a half pound less than my model and flies quite nicely. The C of G has been moved forward by 20mm and comes as a recommended adjustment by several online forum sites. I`ve done a battey shift on my model which also puts the balance further forward at 160mm from the leading edge of the top wing at the centre section. Loads of aileron differential is also suggested together with preparing oneself for plenty of left stick rudder input. Pretty normal for a model of this type. Jungmeister JU-133 - Real RC Reviews www.realrcreviews.com › jungmeister-ju-133

Mike