Announcement

Collapse
No announcement yet.

Classic Motor Glider from Scratch

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #16
    Firstly a big thanks to Torgust for a quick answer to my help call and a program that solves the problem (first time). Secondly, welcome back Ivan, and don't worry too much about the language, these norwegian guys are indecently clever in english and not like we brits who like my old dad used to answer when asked "I speak two languages fluently, english and rubbish". I read with some considerable envy about your Easter outing with 'Golf...Lima Kilo' whilst we were treated to some extreme weather in the mountains and around the coast here in the north.

    As is obvious from the few pictures below, progress over the holidays has been slow - however the pictures will show the method of construction I refered to earlier:

    The first picture shows the current status of the tailplane and the build sequence used. Stage one was to edge join four standard 1/16" balsa sheets to provide one piece large enough to scale and cut the plan view of the tailplane as a flat center core. This is done by taping each two sheets together longitudinally, folding one sheet back on the other along the tape line and running a bead of glue (UHU Hart or aliphatic wood glue) along the tape line, then folding the joined sheets back on a flat surface. Before the glue dries the surface is lightly sanded, not to smooth the surface but to produce some balsa dust which gathers in the joint line and fills any small irregularities. Stage two is to scale the tailplane structure (from the three-view) directly onto the center core, this can be seen partly on the second picture which also shows the partial assembly of the upper half of the structure directly onto the central core. The third stage is as shown on the third picture in which the lightening holes have been cut in the central core between the structural members. The result because of the cross graining of the structure and the central core is a very strong, light and stable framework on which to proceed.

    The tailplane and the elevator have been built as one piece and will be separated at a later stage - the T.E. of the elevator is a thin bass wood (which I prefer to spruce) strip since the elevator has a tapered section which ends in a relatively thin trailing edge. The elevator will be sanded to this section later.

    Very early days yet but that is the current build status.

    Primarily for those of you out there who are new to scratch building, at this stage I will say a few words on tools. To carry out this type of work we don't need many tools but those we do need should be good. Here is a link where most tools needed can be bought at reasonable prices...

    http://www.proopsbrothers.com

    Firstly it is of prime importance to have extremely sharp knives - I have always used surgical knives (scalpel) and mostly the 10A and 11 blades since the large majority of modelling knives that are offered by the average model shop are not nearly sharp enough - a good scalpel handel with a very comfortable plastic handle can be bought from Proops. Buy the blades by the hundred and always work with a sharp blade. Secondly a good quality metal ruler at least 50 cms. long is a necessity - here Linex do a very nice one in aluminium alloy (available at most book stores). I have inserted two sketches of two tools which are indispensible for the accurate cutting of balsa strip parts, one is a guillotine (spelling?) with adjustable cutting angles and an adjustable protractor for finding those angles (both available from Proops). A square, Zona razor saw and a couple of 4B pencils complete our meager tool set.

    So that's it for this round, see you soon.....
    Attached Files
    Last edited by Celtic-Griffin; 11-04-07, 20:15.
    Ken Bates
    Never Mind the Label

    Comment


    • #17
      Flying to Headcorn in the heart of Kent tomorrow to have a cup of tea and a chat with my in-laws. Viz has been rubbish for a couple of weeks now but otherwise hot, sunny and windless. I'll post a report about the flight if there is anything interesting to note.

      The tailplane looks good, looking forward to seeing more. 1/4 scale is pretty big, out of interest what is the law on flying such large models over there? In the UK I believe special permission is required to fly models over a certain size/weight.

      All the best, Ivan

      Comment


      • #18
        Well I went to Headcorn though the poor viz made it feel like I was flying in a goldfish bowl! The view down was fine, but horizonally it was absolutely rubbish and only just inside the legal limit for VFR flight. I had to laugh at my mother-in-law's lack of understanding about how much I can carry in a confined single cockpit. She arrived at the airfield with a bin liner full of Christmas presents for my kids that she'd not posted in time. She thought I could take them all home! As it was I ended up taking about half of them stuffed and tied into any place it could find

        I've flown every day this week and LK's total time is now 35 hours. Yesterday I met up with a friend who flies a Falconar F11-3 which I once had shared ownership of. We decided to do an air to air photo shoot so here are the results for you to see ...

        Falconar F11-3






        Hope you like them .... Ivan

        Comment


        • #19
          Great pictures Ivan - I have experienced the vis you refer to many times from Dunstable (London Gliding Club) - relatively clear vertically but pretty awful horizontally - seems to be a typical senario in the south of England (air polution?) - much worse over Germany.

          Must say from your pictures of 'Lima Kilo' that the more I see the more I know I have choosen the right prototype. Just now I am working to lay out the fuselage sides, I have acquired a quarter scale part kit of the Slingsby Tutor (from Tom Martin RC) which has very much commonality with the Tandem Tutor so I will use very many parts from this kit to produce my project. I would very much appreciate if you could let me have copies of any drawings, sketches, pictures of the mods you carried out forward of the T31B rear cockpit and any details you can let me have of the undercarriage.

          Layout work on the fuselage takes some time so there is very little in the way of pictures to show on the forum just now.

          By the way, both my wife and I flew from Challock (Kent Gliding Club) for some years back in the far distant past, interesting for there we used 'The Archbishop' one of the three Super Tigers from the Tiger Club as a tug.
          Last edited by Celtic-Griffin; 20-04-07, 06:38.
          Ken Bates
          Never Mind the Label

          Comment


          • #20
            It's a small world! I used to be a member of the London gliding club at Dunstable too! I started off gliding in Kent, but from Dover rather than Challock. I then went on to do my PPL A, flying Tigermoths at the Cambridge Flying Group, so that's three links to your last post!!!

            It would be easiest to post you a copy of the drawings, some photographs and the T31 manual (on CD). Can you pm me with your postal address and I will try to get these things off to you in the next few days.

            Ivan

            Comment


            • #21
              Yes, it really is a small world Ivan and I have noticed through a long life in ”hobby aviation” that friends and acquaintances are made over borders, political or otherwise – just as it should be, eh! I am certainly looking forward to the drawings.

              I guess those who follow this thread are now asking, why no activity recently – unfortunately my time has been occupied and have experienced a certain depression around the bruhaha which has occurred elsewhere in this forum – the consequence no progress has been made in the last week or so.

              It has been suggested in forum that this thread is a hidden review of the the Tutor kit which I mentioned earlier so not being able to report progress this Sunday perhaps a little history and background session is in order:

              Background to the Slingsby Model T31 Tandem Tutor on which the T31M subject of this blog can be traced back to three earlier types, Slingsby Type 5 Grunau Baby, the Hols der Teufel and the Slingsby Type 7 Kirby Kadet. The Type 7 was further developed to the Type 8 Kirby Tutor basically the Type 7 with new larger area wings to improve its soaring performance on the request of the Midland Gliding Club based on the Long Mynd (one of the UK’s better known ridge soaring sites). John Sproule who still in his teens was Fred Slingsby’s one and only designer/draftsman was the primus motor behind these developments. In 1950 it was generally recognized that if progress was to be made in british gliding the old solo method of primary training should be abandoned and that two seaters should be introduced. Hence the Type 31 Tandem Tutor was evolved basically the Type 8 Tutor with the additional cockpit added under the wing.

              Martin Simons, in his book ”Slingsby Sailplanes A Comprehensive History Of All Designs” tells us that the tandem layout was prefered to the side by side layout of the T21 Sedberg because of its much more acceptable capital investment but not least because it forced communication through a tube which reduced the instructor’s comment claiming that instructors talk too much anyway!!!.

              It is also interesting to note that the original Type 29 Motor Tutor of which only two were built in 1949 used standard Tutor wings and tailplane. It may also be interesting to some that the further development to the Type 30 Prefect exists as one example in Norway, LN-GLV imported and restored to flying condition by yours truely and which I believe is still flying with a member of the Seilflyhistorisk Forening.

              All this waffle is just to demonstrate that it is the T31M that is the subject of this thread and the use of the Tutor kit is purely to avoid tedious part cutting by utilizing the many common parts.

              Since the Hols der Teufel is probably the glider which is least known by you guys out there (and add a little colour to an otherwise drab rambling) I am appending some pictures of a restored example now flying with the Vintage Glider Club. Here you can already see the now familiar wing and tailplane layout of the Type 7 Kirby Kadet and their similarity to a number of other gliders from Slingsby.

              By the way a further development of the T31B Tandem Tutor was the T35 known as the Austral and built at Kirby Moorside (Slingsby), it incorporated extended span wings and an enlarged tail and gave the glider a worthwhile improvement in soaring performance for the strong thermals in Australia its destination.


              Back to the building board in the hope that I will have some progress to report next Sunday.
              Attached Files
              Last edited by Celtic-Griffin; 29-04-07, 14:55.
              Ken Bates
              Never Mind the Label

              Comment


              • #22
                I had a simple thirty minute bimble tonight. Viz was rubbish, but
                just as I'd decided it was no fun and started my approach to land, a
                Jodel appeared on my port wing and waggled it's wings ... a
                challenge! I turned straight in and he couldn't out turn me. If I'd
                had guns he'd have been dead meat as he'd made the mistake of not
                using his superior speed to shake me. Then he climbed ... but not
                fast enough (I can squeeze over 800 fpm if I try) again, I'd have got
                him! ... But then I'm not aggressive, so I flew straight and level to
                let him formate about fifty yards off my starboard wing. We waved and
                I pointed down to indicate that I had to land (no fuel) so couldn't
                play. He again waggled his wings, but this time to say goodbye. I did
                the same, and down I went! Shame as it's rare to have such an
                encounter. The last time I had such an airbourne dogfight was in my
                old VP2 when I bounced a DH Chipmunk (but he was skilled and I'd have
                been dogmeat!) .... I love these simple aeroplanes! Nobody ever seems
                to do these things in spamcans? I think the assumption is, anybody
                flying aeroplanes of character is likely to be "up for it".

                Bloody right!!!!

                Ivan

                Comment


                • #23
                  Hi Ken,

                  Did the drawings arrive ok? I forget to scan the general layout, so I'll take a high definition photo of the drawing and send it.

                  All the best, Ivan

                  Comment


                  • #24
                    Originally posted by ivanmanley
                    Hi Ken,

                    Did the drawings arrive ok? I forget to scan the general layout, so I'll take a high definition photo of the drawing and send it.

                    All the best, Ivan
                    Cheers Ivan - yes the drawings and CD arrived late yesterday so I will spend some time over the weekend studying them - you must let me have an idea of the expense you have incutrred preparing them. Some of the detail pictures on the CD I will put out on this thread as soon as possible so that you guys out there can get an idea of the detail I now have particularly for the U/C as this will be a little nut to crack during fabrication.

                    Once again thanks to Ivan I have detail which normally a scale modeller would not have.
                    Ken Bates
                    Never Mind the Label

                    Comment


                    • #25
                      How's the building going? As this is my newspaper, I'm in here everyday to check for updates of the progress! =o)
                      Marius

                      Comment


                      • #26
                        If anyone's interested, I've posted a picture and video complilation of G-BZLK on Youtube. The url is

                        Ivan

                        Comment


                        • #27
                          Originally posted by _marius
                          How's the building going? As this is my newspaper, I'm in here everyday to check for updates of the progress! =o)
                          Sorry to say the recent bruhaha on this forum has rather knocked the wind out of me and I have had a little problem to summon up the steam to go ahead - fortunately with me these dark moods tend to go over rather quickly and the enthusiasm returns. Just now Marius, I am laying out the fuselage sides and modifying the drawings from the TM Tutor kit to T31M status particularly front of the rear cockpit. This work is vastly helped by the drawings of the prototype nose and undercarriage which arrived from Ivan just before the weekend. The undercarriage is quite a nut to crack since I have set myself the task to reproduce the prototype in detail and function, not just use some bent piano wire. The drawing work is not so easy to photograph so it will be when construction starts that I will be able to introduce some pictures here, hopefully quite soon. I am, however including some pictures of the undercarriage and if any of you guys out there have any suggestions on materials and methods, I will be very pleased to see your contributions here.

                          One further question for you Ivan, looking to the wings, is your aeroplane fitted with original T31 spoilers?
                          Attached Files
                          Ken Bates
                          Never Mind the Label

                          Comment


                          • #28
                            Yes it still has the original spoilers ... and very useful they are too!

                            Comment


                            • #29
                              All quiet, any progress?

                              Hoping to fly to the G-VFWE (Great Vintage Flying Weekend) tomorrow, but weather is looking dodgy, so I let you know how I get on.

                              Ivan

                              Comment


                              • #30
                                This thread will now be prepared as an article and published elsewhere and Celtic-Griffin will no longer contribute to MFN.

                                Ivan the reason for this is burried in the norwegian elsewhere on this forum - I will contact you by e-mail and explain.
                                Ken Bates
                                Never Mind the Label

                                Comment

                                Working...
                                X