GliderIreland - Ireland RC Forum - Flying Model forum in Ireland
Gliders => PSS => Topic started by: JohnPearson on October 19, 2010, 22:09:55 PM
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Hi All
Well it's time to get building for next season, and after looking at a few designs over this year's flying season, i have decided to go with a B57D. This is the USA upgrade of the British Canberra, used as a sky plane by the US airforce in the 50's
(http://www.gliderireland.net/forum/images/uploads/JohnPearson/martin_rb-57d.jpg)
The wing span is 106" and it is balsa fuselage and foam wings. I have started building and will post a few pics of the progress so far soon!
johnp
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=P~
And that's pretty much all I have to say ! :D
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Those wings will certainly generate a lot of lift John. Looks like a nice project.
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That’ll be a more manageable size than the big B52, and I would presume produce far less drag with only two engine pods. Hopefully I'll see this one fly off Big L. :D
Are you going to make the design yourself John, or will you be using existing plans?
K.
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Hi Keith
This one is from existing plans and yes! this model will fit inside the car. I got the plans and vacuum parts in a traplet sale £20.00 the lot, I think? anyhow at 106" wingspan the B57 is a nice size. Here are a few pics of the build so far:
(http://www.gliderireland.net/forum/images/uploads/JohnPearson/framework.JPG)
The formers have a ply middle with balsa skins on both sides.
(http://www.gliderireland.net/forum/images/uploads/JohnPearson/enginepods.JPG)
Nice set of vacuum engine pods, I am thinking of installing two fan units into these pods later for flying of the flat.
(http://www.gliderireland.net/forum/images/uploads/JohnPearson/CIMG1798.JPG)
Long canopy for two pilots nice!!!
So far I have had one problem, after getting the fuselage formers lazer cut from lite ply according to the template provided, the formers are to short according the the plan by about 1/2", therefore I had to move the bottom span up to link with the formers. right pain in the a*!/*
Anyhow hope to have one side finish over the weekend.
johnp
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John Pearson, Let me get this right???…………..You decided you were going to build this model, from plan, on Tuesday, (2 days ago.) And now you’re telling us that you intend to have one side of the fuselage finished by the weekend!!! :shock: :shock: That is Outrageous!!
(Makes me feel totaly inadequate. :oops: )
Just as an aside,…………….. On what basis will you asses what size of fan units and motors to use if you decide to fly this as a powered model? :?:
K.
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Hi keith
This model has a large wing span (good lift), therefore if i can keep the weight down, I reckon that two 70mm fans with two hot motors, should do fine. i want the model to fly at a scale speed, so this setup should provide a good thrust to weight ratio.
I will test the model on the slope first to get the CofG right and the control throws sorted, then later add the fans.
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Quick question………..what do you define as a “Hot Motor” :?:
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HET Typhoon 2W-20 3300Kv (700W) Brushless Inrunner Motor, would be a hot motor on a 4 cell lipo
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So far I have had one problem, after getting the fuselage formers lazer cut from lite ply according to the template provided, the formers are to short according the the plan by about 1/2", therefore I had to move the bottom span up to link with the formers. right pain in the a*!/*johnp
I know how you feel. The plan I have for the Skylark 2 is not very accurate as well. I will have to make some adjustment to the formers. I'm also redesigning the wings myself using a different aerofoil. Where did you get the parts laser cut? Did they come from Traplet?
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This is interesting and worrying.
Buying plans that someone has drawn up is supposed to mean saving you work. :(
If the plans have to be 'adjusted' it makes you wonder if you couldn't have drawn the lot from scratch. :?
I have had this problem in the past (so who hasn't), and had naively thought that with modern 3D cad systems it would be a thing of the past.
On the aerofoil.... what software do you use? If any :wink:
I've seen Compufoil talked about a lot.
Ron
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I have had this problem in the past (so who hasn't), and had naively thought that with modern 3D cad systems it would be a thing of the past.
On the aerofoil.... what software do you use? If any :wink:
I've seen Compufoil talked about a lot.Ron
Hi Ron. Nice to see you back on the Forum again.
I am very certain the plan I have was not designed using 3D Cad software. If it was I would say it would be much more accurate. It looks like it's a hand drawn plan (when I mean hand drawn I mean with rulers etc. not free hand).
The software I'm using for the wing is called Profili Pro 2. Its quite a good software. You can get it here http://www.profili2.com/eng/default.htm
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Thanks Alan,
Had a few health problems in the family, but getting sorted now.
I didn't think there were any old school, pencil and ruler draughtsmen about still.
Maybe it's an old plan?
Hope the one I've ordered (Skylark 1) is a bit better.
That Profili 2 looks interesting.
I'll give that a try.
Ron
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Hi Ron,
You also have Tracfoil (that's what I use), but I usually use those software to export the dat in the CAD program.
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It might be an old plan. But it does say copyright 2007. But looking at it you can defiantly see it its not a Cad plan. There are lots of small errors here an there.
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Hi Ron,
You also have Tracfoil (that's what I use), but I usually use those software to export the dat in the CAD program.
Hi Fred.
With Profili Pro 2 you can export everything to a dxf. file so you can use it in a CAD program.
By the way John sorry for hijacking your build log.
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I know, I also have Profili, but for a design point of view, the features they offer are quiet limited if you want to do something that is not planned by the software, but for a quick rib print for a straight build, they work great! :D
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hmmm :?: Must have a look at Tracfoil then :?: :?:
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Well, no, I meant Tracfoil and Profili (and the like) by that.
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Oh I understand now. I think Compufoil can do much more.
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Yes sorry John for the hijack :oops:
Looks like Compufoil can do more, but also looks like you need to buy the aerofoils or something on a memory stick. :?
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Hi Ron, yes it's easy to get side tracked on this forum.
Well I have managed to get things moving again ( weekend panic with the family!), I have started sheeting the fuselage and hope to have this completed by the end of the week. The plans state that this sheeting should be done with lite ply, however with the poor supply of balsa and ply up here in the North from model shops, and the increase in postage costs from across the water, I have used lite balsa, which will be glassed later for strength.
(http://www.gliderireland.net/forum/images/uploads/JohnPearson/b57d2.JPG)
Progress so far, start of sheeting on fuselage.
I will update later this week,
JohnP
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Well, another bit of building done tonight.
(http://www.gliderireland.net/forum/images/uploads/JohnPearson/CIMG2041.JPG)
johnp
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Very good john, coming along nicely I think describes this build. :clap:
I'd just like to go back to something you said a few days ago.....(I'm still trying to figure out what defines a HOT motor :? )
HET Typhoon 2W-20 3300Kv (700W) Brushless Inrunner Motor, would be a hot motor on a 4 cell lipo
I've had no experience with inrunners.(I've a fair bit with outrunners though)
Looking at the tech. spec. of the above I see this motor has "2 wind" :shock:
What is a 2 wind motor?
And what does "2W-20" mean?
Yes, I know this is all boring stuff for you, :roll: but Uncle Keithy needs to know these things :!:
K.
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Yes, I'd be very interested too.
I'm not up with the latest jargon on all this motor stuff :oops:
Ron
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Keith, nearly every motor producer has mixed up ways of telling us data through the numbers they us for their motors !
The Het motor is a 2 turn !
What the 20 stands for !!!! number of wires per wind ¬! number of stators, number of how many times the little chineese man cut his knuckles whilst winding the motor ! it could be many a thing but not important.
Aiden might have the answer .
What you need to know is the Watt output, on the desired battery and prop/fan unit.
I am not a lover of Thypoon motors,
I am a mega motor fan lol.
Screaming motors should be banned !
Richard
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Keith, nearly every motor producer has mixed up ways of telling us data through the numbers they us for their motors !
The Het motor is a 2 turn !
What the 20 stands for !!!! number of wires per wind ¬! number of stators, number of how many times the little chineese man cut his knuckles whilst winding the motor ! it could be many a thing but not important.
Richard
Yes I know all producers use different publish data about thier motors. Infuriating isn’t it! :!:
But look, ….I’m just a humble, simple minded Englishman. You have to be gentle with me.
2 turn??? Are you saying that each coil / winding would only have 2 turns?
Just need to get this right in my head.
Yours, desperately seeking answers,
Keith
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Just watched that vid. He flys very nose up doesn’t he…….is that what they call a “Head Up Display” :lol: :lol:
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DOH! I've put my last post in the wrong thread.......... :!:
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Keith, nearly every motor producer has mixed up ways of telling us data through the numbers they us for their motors !
The Het motor is a 2 turn !
What the 20 stands for !!!! number of wires per wind ¬! number of stators, number of how many times the little chineese man cut his knuckles whilst winding the motor ! it could be many a thing but not important.
Richard
Yes I know all producers use different publish data about thier motors. Infuriating isn’t it! :!:
But look, ….I’m just a humble, simple minded Englishman. You have to be gentle with me.
2 turn??? Are you saying that each coil / winding would only have 2 turns?
Just need to get this right in my head.
Yours, desperately seeking answers,
Keith
Hi Keith, yes it is actual 2 turns per stator !
Each turn of wire is made up off several sub wires !
Maybe this is were the 20 comes from ! :clap:
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Right,…………………..yea’ don’t know what usefulness stating that each winding used 20 core multi stranded wire would be. (possibly it would make the windings more resilient to breakage from vibration?!) Thanks for your help Richard
I’ll be back with some more questions another day :lol:
Keith
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Hi Guys
Keith, don't get to hung up on motors, Richard is the man when it comes to the tech stuff about motors. The main factor for these little jets is weight!, keep it light and you will not have to use a big watt motor. Check out the various forums on these models, use what others are using, that's my best advice. My alfa mig15 flys great on a small inrunner motor 3500kv I think, on a 3cell 1200 lipo, the jet is fast and flys in a scale fashion. I tried a big battery once to see if the speed could be increased, yes the fan was producing more thrust, however with the extra weight due to the battery, the model didn't fly any faster. so I went back to the smaller lighter battery, shorter flights but better proformance.
When it comes to these foam jets, it's best to keep it simple and just enjoy flying to model at a nice comfortable speed.
Bye the way, Keith sorry about the little accident with the squall, i am sure you can glue it back together.
Your call sign has now been changed to 'Crushed Iceman' :lol: :lol:
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"Crushed Iceman" Hu?......... :evil: ........( :lol: )
That's almost funny John!
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Hi Guys
Keith, don't get to hung up on motors,
But I like learning John....I have a lust for knowledge.
I used to have a lust for women, but now it takes me all night to do, what I used to do all night! :oops:
k.
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Still no building at the moment, the workshop is soooooooo! cold
(http://www.gliderireland.net/forum/images/uploads/JohnPearson/cold.jpeg)
johnp
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Here's something to warm you up John.........
(http://www.gliderireland.net/forum/images/uploads/Happy%20Days/avatar_17528.gif)
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There,………feeling a little warmer now are we?
It’s actually part of a video I made earlier this year of my misses. :wink: ....... (I wish! :lol: )……. (so does she!! :lol: :lol: )
Keith
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Lovely :clap:
Can she fly planes ?
How does she like hold the sticks !
MODE 1 OR 2 lol
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Answers are:………
“Can she fly planes” = Sort of. She crashed the last trainer nose in. :cry:
“How does she like hold the sticks” = Finger and thumb job. But very Tightly! :twisted:
“Mode 1 Or 2” = well……….more AC / DC really. :P
Oh Richard, you are naughty!
Keith.
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mode one or two
she can have a go on my stick any time :wink: :lol: :lol: :lol:
:lol:
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Come on John were are spoiling your thread so get the finger out and give us an update on your build.
Richard
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'Look you two' I am only human!!
First I am frozen to death in my workshop, now I am hot under the collar when I look at Keith's recent post showing that speedy model with the fine lines, a fantastic tail plane and a great set of air breaks 'wow thank you Lord for big gliders!!!!' :P :P :P :P