Here is a list of all the postings Birgir has made in our forums. Click on a thread name to jump to the thread.
|Thread: Bleriot XI|
I ‘m still practicing flying and trimming my Bleriot. Now when new season is coming I’m re-reading the suggestions made on this thread preparing for the first flight this summer. Before last year’s season was over I managed to trim the elevator, and CoG for a levelled flight at a little less than full throttle.
The CoG is about 14 cm from the LE edge which is about 4.5 cm behind the spot suggested by Boddo. I now have 425 gr. of lead up front. Bearing this in mind I would think that the problem would be a tail-heavy model rather than nose heavy. BUT the trim needed for the elevator is a down trim of about 12 – 15 deg. (Remember the split stabilizer has a big elevator area)
I’m not sure what I can read into this. Is the stabilizer creating lift which needs to be corrected by down-trim elevator?
This trim must be creating unwanted drag. I wonder if it would be wise to alter the incidence of the stab a little by putting a 1 or 2 mm shims of plywood between the fuselage and the LE of the stab and reducing the down trim of the elevator.
All comments and suggestions are appreciated.
|Thread: Mini Super|
Thanks DeeBee - this is a fascinating story
I’m a proud owner of a Keil Kraft Mini Super. It was built by me and my dad in the early seventies, ‘72 I think. It was a Keil Kraft kit and I still have the original box and plans.
It has had several rebuilds and some modifications over the years but I’ve been flying it every summer since 2013 when I did the last rebuild. I also did some modifications, ailerons, less dihedral, steerable front wheel and so on.
It has gained some weight over the years, just like some of us and today it is 1.835 gr (64.7 oz). The last modification, a bigger fuel tank welded together to fit available space, added about 40 gr. The original kit had a tiny tin tank.
The wing area is 2.267 sq. ft. not counting the middle section so the wing loading is up to 28.5 oz per sq ft. in my model. That is a bit heavy and the landing speed is also a bit fast but a heavier model suits the windy weather in Iceland very well.
The original plans in the kit came on two sheets, clearly marked 48” wingspan and are signed by Ernie Webster if I’m reading it right. I didn’t know that David Boddington had a hand in the design. Can anyone explain to me how that came about and who is the original designer of the Mini Super?
|Thread: LED-lights DIY|
Even though I had much fun implementing the navigation lights into my Mini Super they came out a bit dim.
Next time I would follow John Stones suggestion earlier in this thread and buy a ribbon to pull the leds out of. It can be bought in any length
The link is: LINK
|Thread: Ask..Peter Miller|
|Thanks kc 😂|
I look forward to reading the missing parts.
I’ve already ordered your book Designing Model Aircraft. It can be bought from Amazon.co.uk, there are still a few copies left:
Good evening Peter
I hope your health is coming back.
I find this middle article part very interesting and would very much appreciate if I could see the other two.
Best wishes from Iceland,
Edited By Birgir on 03/01/2018 16:05:23
|Thread: Bleriot XI|
Thanks for this
I think I’m beginning to understand the task at hand and getting a better understand of the problem.
I’m used to land my trainer using the throttle to control the decent, (i.e. elevator – speed, throttle – height) but the trainer is trimmed for level flight at ca. 60% throttle. And a proper decent at about 40 - 50% throttle.
The Bleriot isn’t trimmed properly at all. I fly it at full throttle using the elevator to maintain height. This is the first thing I must change.
My limited experience with the Bleriot tells me though that I have a very narrow band of throttle change to play with, much narrower than in the case of my trainer.
So, next flight the task is to trim for levelled flight at something less than full throttle. Full throttle should then increase height and something less should cause levelled decrease in height.
Because of the narrow band in throttle change, it is possibly wise to install throttle curve in my TX. For example, setting 50 – 75 – 90 at 25%, 50% and 75% stick position resulting in the last 10% of throttle change spreads over the top 25% of stick movement.
When this trimming is accomplished I should be able to practice a few low passes hopefully resulting in a smooth landing in the end.
I would welcome any views and warnings about this approach.
Yesterday I managed to do one flight with my Bleriot. I went back to 10 x 5 prop and 425 gr of ballast. I also reduced the elevator throw about 25%.
The take-off went very well, strait into the wind (4-5 m/s) and I managed the model better than before, did a couple of circles and a figure eight.
Then the dreaded landing approach. When flying my trainer, I usually glide in on half a throttle and then reduce the power to let the model loose height.
When trying the same approach with my Bleriot it looks like I reduce the power too much and too soon and it ends in a kind of “drop down” landing and a broken landing gear.
I notice that John talks of “motor in for a smooth touchdown” on the landing approach.
I would sure like to hear a better explanation of this approach and how to land a Bleriot with under cambered wide wings and a marginal powerhouse.
All comments are welcome.
Thanks Donald, I like your advice.
I will hold back on changes and practice with 10 x 5 and 425 gr.
The problem is though that the flying season is probably over here in Iceland for this year.
Looks grate and very well balanced in the air
Thanks Jon, I will keep this in mind.
Here is a video that John might like 😊
Grate news, looking forward to more pics
Now the wing is fixed and testing can go on. This time I used 10x5 prop and 425 gr lead.
The model still needs a bit up elevator to keep level and could also do with more speed. Later I tried 10x6 and 400 gr of lead but dropped a wing turning too soon and broke the landing gear. I ‘ve already started to fix that.
The flight in this video taught me to leave the phone in the car while flying.
Edited By Birgir on 19/08/2017 22:14:50
The weather here in Iceland has not been very suitable for my Bleriot project lately. Never the less I’ve been able to do some flights. As some of the readers of this thread may remember there are two main tasks at hand at present. The first one is adjusting the CoG losing some of the lead up front and the other one is to select the best prop to be able to get the most out of the rather small SC30FS.
On D. Boddingtons plan the CoG is marked about 10 cm from the LE. To get the CoG to 11 cm I had to put about 600 gr of lead on the landing gear and therefore it was very difficult to get the model up to speed on the runway with the rather small engine. When in the air I had to use a considerable amount of up elevator to keep it level. I took Donald’s Fry advice and took off 25 gr of lead after each flight. Now I’m down to 425 gr so I must have had more than eight flights until now. The model still needs an up elevator, but considerably less than before.
During this time, I’ve only had two crashes, not counting some hard landings and minor injuries. Both was of course my own fault. The first one was fixed by re-gluing the landing gear but the latter one was more drastic. The reason for that crash was that once again I didn’t follow the rule of heading directly into the wind until suitable height is reached. If you allow the model to turn to early it will drop a wing and tip stall into the ground. (I needed three instances to get this; understand, practice and remember.)
The model is already fixed and ready for take-off once again.
I’ve been using 10*4 prop but as the engine runs in, it gets more power and I have now switched to 10*5 and by that I’ve got a little more speed for take-off.
It might be wise to try 9*6 or 10*6 as I could still do with a little more speed for take-off.
Now I´m off for Texas for a fortnight so further test must wait a bit.
Note to moderator:
Edited By Birgir on 03/07/2017 10:34:29
|Thread: Vintage Wheels|
I also went the DYI route to make wheels for my Bleriot.
There are some pictures on my web: **LINK**
If you choose English and click on the photos there is a little explanation.
Later I used neoprane cord instead of foam.
Edited By Birgir on 11/05/2017 22:04:18
|Thread: Spring is Here....|
The spring will also soon arrive here in Iceland so I went to the field this morning with my old trainer, the Keil Kraft Mini Super and practiced a few landing approaches just to loosen up my fingers for the summer.
Edited By Birgir on 30/04/2017 22:31:06
Edited By Birgir on 30/04/2017 22:38:55
|Thread: Have you passed the model flying/building bug onto anyone else?|
I guess you have to start early if you want to succeed, this is what we call "early intervention" in my line of work.
|Thread: Forum members' new models: Let's see them.|
When the weather is impossible and all your models are in a mint condition the only thing you can do is to design a new colour scheme for the field box and paint it.
Edited By Birgir on 02/03/2017 20:58:57
|Thread: Field Battery|
Hi Steven and welcome back
I’m an IC user and have been using the same Lipo 2s 4000mAh battery for my electric starter for the past three years. I almost never charge at the field and my starter battery only needs a recharge a few times a year.
If you are going to build your own field box feel free to download my excel sheet of an adjustable field box plan
You can see my starter and starter battery on the table.
Edited By Birgir on 18/01/2017 17:50:08
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