Birgir
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Posts posted by Birgir
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Yes, the red thing is a cap.
The setup is similar to this picture but the fuel pipes go through the bottom of the tank/flask instead of through the cap and there is also a fill pipe. The fuel pipe is a bit above the center.
This picture was taken during the last rebuild.
So now I must make a tool I can use to change clunk hose through the opening.
B.
Edited By Birgir on 27/02/2015 15:16:38
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Hi and thanks to everyone for sharing their thoughts.
I finally made the Baker-test this morning and 12 points goes to Bert Baker
The clunk-pipe nipple is at the top of the tank so with a half tank of fuel I ran the motor full speed to be certain that the problem was still there. Then I turned the model upside down so the clunk-pipe was fully submerged in fuel and Vola! No problem. I did this several times to be absolutely sure.Of course there is a small chance that there is something wrong with something else that disappears when the model is turned over, but I think that the clunk pipe is a reasonable suspect.
So now I only have to figure out a way to change clunk-pipe through the tank cap. Doctors do heart surgery thru smaller holes so it must be possible.
Until then my Bleriot is coming along nicely.
Thanks,
B.
Edited By Birgir on 27/02/2015 12:12:22
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Thanks kenking
I like your theory. If we take this line of thought a bit further it could also explain the forming of bubbles in the fuel line from tank to carb. As you probably know, when the pressure drops in a fluid, a vapour bubbles can form, just like boiling.
The boiling point of fuel must be rather low so this is probably not as far-fetched as it sounds. The boiling point of methanol is around 65 deg. so the fuel could have even lower boiling point than that. (I’m not going to test it.)
I wonder if it is possible to test this theory by putting an adjustable clamp on the fuel line from tank to carb. If that part is made a little narrower a cyclical phenomenon in the clunk hose should stop even though the engine might not reach top rev.
B.
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Well, we actually do have Iceland in Iceland too – you know – so I got the pun, but thanks for the concern.
Maybe I will send some burgers over when I've done the test
B.
Edited By Birgir on 22/02/2015 19:01:41
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Hi Ken
In Iceland
B.
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Hi
I‘m still waiting for an opportunity to perform the Baker-test, i.e. checking if the problem still exist if the clunk pipe is fully submerged in fuel. Because the test needs to be performed outside I must wait for suitable weather, and it can be a long wait around here.
While waiting I’m forced to spend time on my next building project.
B.
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35 miles each way, but I buy most of my stuff online from Pegasus Models. Their online service is also very good and personal.
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“Our youth now love luxury. They have bad manners, contempt for authority; they show disrespect for their elders and love chatter in place of exercise; they no longer rise when elders enter the room; they contradict their parents, chatter before company; gobble up their food and tyrannize their teachers.”
Socrates, 469–399 B.C.E
B.
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I do
My Keil Kraft Mini Super, build in 1973 is still going strong
This video is from last Saturday, 24th of January
Pictures of the last rebuild can be seen at **LINK**B.
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Yes, Peter, I've met Murphy once or twice
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Thank you all
I favour the Bert Baker test and will do that.
It will determine if the last theory is true or false
I’ll let you know how it turns out
B.
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Thank you all for good ideas.
It looks that everyone agree on that the problem is most likely due to “false” air in the system somewhere, i.e. from the tank to the engine cylinder. So I will work from that theory.
Whereas the engine and tank are closed in a balsa cowl and difficult to access it is important to give this a good deal of thought before any decision is made
Let’s play some Sherlock Holmes.
Theory: Air is drawn in to the system at an unknown place
Facts:
1. The system can be divided in to two parts, A, being the engine, B, being pipes and hoses leading from tank to carburettor.
2. Air bubbles have been seen in the fuel line from tank to carburettor at high speed. (New knowledge)
3. Engine is new but some part of fuel line and the tank are a few decades old.
From those three facts we have reason to believe that it is more likely that the problem is in system B. rather than system A.
Tests
1. Does system B hold pressure for a period of time? This can be tested by closing tubes leading to muffler, engine and fill cap. Blow a little air into the system and see if it can hold pressure.
2. Does system B hold vacuum for a period of time? This can be tested by closing tubes leading to muffler, engine and fill cap. Suck a little air out of the system and see if it can hold vacuum.
I’ve already done test 1. and 2. and the system holds pressure and vacuum for at least 1 minute. So I conclude that the system B as a whole is air tide.
Fact 2 does although point to some malfunction in system B
New theory:
The hose inside the tank is leaking.
How possible is that? If the top of the hose where it connects to the nipple going out of the tank leaks, is it possible that he engine can suck some air out of the tank into the fuel line. Remember that there is some pressure in the tank from the muffler.
I would welcome any ideas on that before I start tearing my model apart.
B.
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Hi
I have an ASP S21A engine in my Mini Super and need some help adjusting it. Although the model is over 40 years old the engine has just had between 10 and 20 flights so it is just about finished the run in period.
The engine is very easy to start but when throttle is fully opened the rev goes up and down without me moving the stick. In the following video you can hear how it sounds.
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The question is, what could be the cause?
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To lean mixture
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To rich mixture
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Wrong glow plug
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Vibration foaming the fuel, leading to air in the fuel hose
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Another cause…
Any thoughts and ideas appreciated
B
(BEB: proof reading is also appreciated)
Edited By Birgir on 25/01/2015 11:33:56
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After having pulled my stuff around in old shoeboxes for a couple of years, I decided to build myself my own Field Box. Of course I wanted my Field Box to fit my stuff exactly so instead of drawing a plan I made an Excel sheet. The Field Box has three drawers and open shelves at both ends. In the Excel sheet you can put in the dimensions you want and get a list of parts you need to make it.
If anyone can use this Excel sheet please feel free to do so and to distribute it as you like.
B.
Edited By Biggles' Elder Brother - Moderator on 12/01/2015 09:08:25
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Hi John
Where I live we often see the Northern lights, but sadly I‘m not a good photographer. If you would like to see some Icelandic pictures of the northern lights, try to put the Icelandic word „norðurljós“ into a Google Images search.
B.
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Hi Brent and welcome to the Mini-jazzers
I finished building mine in the end of July and have flown it several times. I use OS 0.15 and it has quite enough power for everything I´m capable of doing.
I made a build log at **LINK** It is in Icelandic but you can choose a translation on that page that uses google translate. Not perfect but helpful if you don’t speak Icelandic.
I followed the plans pretty much. I used mini servos with plastic gear but would recommend using metal gear, at least for rudder. I’ve already broken one but abandoned take off so no harm.
If you are taking off from a grass field, using a little bit bigger wheels might be wise, and if you are using a tail wheel you should take that into account when building the undercarriage so the take off angle is the same.
Welcome again and best wishes for your road back to good health.
B.
Edited By Birgir on 06/09/2014 14:03:50
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Congratulations John, have you flown it yet?
Mine is 982 gr without fuel so it is probably around 2 lb 6 oz with full tank (4 fl oz)
or about 1080 gr. (Sorry I’m not too familiar with pound and ounces).I use 0.15 two stroke, so the difference in weight is probably not that much.
Birgir
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Posted by Jamie sawyer on 01/08/2014 21:44:01:
John there is nothing wrong with your colour scheme. I think it looks good. I got an email today that the plan was on its way to me. Fingers crossed its here tomorrow. As a rule of thumb what engine are you guys using ?? Is it 10s ,12s or 15 Ic engines ??
Thanks
I´m using a .15, I had from an older model. The CG came out fine without any extra weight. I've only used 8x4 prop but perhaps it can manage 9x4.
B.
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I’m sorry for your mishap Kev, good to see it fixed.
I would go easy on the EXPO. I tried it on my FF-117 and the experience was something like, nothing – nothing – everything. I had to spend quite a lot of time searching for that model in a nearby stinging nettle field.
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I flew my Mini Jazz for the first time tonight - WOW.
I´m looking forward to lot of new maneuvers to learn.
B.
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Posted by Kevin Fairgrieve on 31/07/2014 08:16:56:
Nice model.
Have you flown her yet?
Kev
I hope Google translate works.
Nice líkan. Hefur þú flogið hana ennþá? Kev
Thanks Kev, your Icelandic is very good.
I haven‘t flown the model yet, it is still too windy around here.
B.
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Hi everyone
This is my first post to this forum but I have been reading it a lot.
I finished my Mini Jazz yesterday and just wanted to thank you all for inspiring posts at this thread and show off with a picture of my model.
A building thread in Icelandic (Thank God for Google translate) and some more pictures can be found at **LINK**
Now I just have to wait for suitable weather for the maiden flight
Regards,
Birgir -
Santa ???
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Please count me in too -
Don't forget Santa lives in Iceland
B. (from Iceland
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Help needed
in IC Engines
Posted
Problem solved!
I decided to do a "keyhole surgery" and replace the clunk tube. When I got the clunk tube out for inspection there was nothing wrong with it BUT in the clunk itself there was a wire filter the was partially clogged. I replaced the clunk and the tube.
After the operation, I tested the engine and now everything seem to be alright.
So after all, it was Kenking that was right – at least partially – the problem was due to disturbed fuel flow thru the clunk tube.
Thanks for everyone’s help, it’s been a pleasure working on this problem.
B.