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Jul 07, 2013, 08:03 AM
Learning to make
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Help with designing a Cirrus Vision SF50?


This post is out of date, See post #28 after this post.

Hi everyone!

I've noticed a lack of Vision SF50 designs(It's one of my favourite Airplanes)
and as I want to make one in the near future(2-4 months time) I've decided
to make a 1/13 scale EDF foamie design.
First of all, so you know what the Airplane I'm talking about looks like:
http://en.m.wikipedia.org/wiki/Cirrus_Vision_SF50
So I figured out that 1/13 scale equals:
Wingspan: 90 cm
Length: 72.4 cm
Height: 24.6 cm
And just for a joke: (Or ultra accuracy!! )
Cabin Width: 12 cm
Cabin Height: 9.5 cm
I'm aiming for a less than 1.5 Lb AUW weight with EPP body, Retracts, Ailerons, V-tail, and 51mm EDF unit. Ideally I want an AUW weight of 1 Lb, I can forget about Ailerons and use just dihedral and the V-tail if necessary to keep it light.

Regarding parts, are there any better choices than these??
51mm EDF: (no motor)
https://www.hobbyking.com/hobbyking/s...inch_51mm.html
Motors: (Can you help me pick one? I'm looking for a lowish kv for slow flyer)
C10 Micro brushless outrunner:
https://www.hobbyking.com/hobbyking/s...er_2900kv.html
Turnigy 1811 2900kv:
https://www.hobbyking.com/hobbyking/s...er_2900kv.html
Turnigy 1811 3800kv:
https://www.hobbyking.com/hobbyking/s...or_3800kv.html
If there is a better motor and/or EDF(I'm sure there is!) can you tell me about it?
I'm aiming for the my SF50 to fly at a "slow scale looking speed" if possible.

Thanks a lot!
Last edited by fossil1999; Jul 11, 2013 at 04:23 AM.
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Jul 07, 2013, 08:27 AM
Registered User
D_FAST's Avatar
1lb is gonna be hard to achieve with retracts, unless your talking mechanical.
A 35" Wing span i don't think a 50mm edf is the way to go. your more in the range of a 64-70mm
just to give you an idea

edf shroud -50g
motor -70g
20amp Esc-30g
3s lipo- 100g-150g
2x servos - 20g

the basic and your already at 250-300g which is pretty close to 3/4lb and you dont even have an airframe yet.
Jul 07, 2013, 08:44 AM
Learning to make
Thread OP
Quote:
Originally Posted by D_FAST
1lb is gonna be hard to achieve with retracts, unless your talking mechanical.
A 35" Wing span i don't think a 50mm edf is the way to go. your more in the range of a 64-70mm
just to give you an idea

edf shroud -50g
motor -70g
20amp Esc-30g
3s lipo- 100g-150g
2x servos - 20g

the basic and your already at 250-300g which is pretty close to 3/4lb and you dont even have an airframe yet.
Yes, I'm not planning on using Hydraulic Retracts, but I see what you mean.
So you think a 64mm EDF will do for a 90 cm wingspan plane? Sounds right to me and that if I want a slow flyer I need to make the wings bigger?

Thanks a lot for your help
Jul 07, 2013, 08:48 AM
Do it Right, the first time!
CoolerByTheLake's Avatar
Quote:
I'm aiming for a less than 1.5 Lb AUW weight with EPP body, Retracts, Ailerons, V-tail, and 51mm EDF unit. Ideally

A most commendable goal, I wish you well. On my current build I'm hoping to stay under 11lb!

Regarding the Cirrus Vision SF50, funny thing, I live just across the Hwy from the Cirrus plant, and I've only seen flying a few times.

Good luck on your build, I'll be watching your progress.
Jul 07, 2013, 09:05 AM
Learning to make
Thread OP
Quote:
Originally Posted by CoolerByTheLake
A most commendable goal, I wish you well. On my current build I'm hoping to stay under 11lb!

Regarding the Cirrus Vision SF50, funny thing, I live just across the Hwy from the Cirrus plant, and I've only seen flying a few times.

Good luck on your build, I'll be watching your progress.
Wow... nice to meet someone who has seen the SF50 flying!
As for only seen it flying a few times, well there is only 1 of them at the moment.
But anyway! What is your impression of it? I think it's a lovely little Jet Airplane!
Thanks, and good luck on your build! What's it modeled on? and how big?
Jul 07, 2013, 09:28 AM
Do it Right, the first time!
CoolerByTheLake's Avatar
What is your impression of it? I think it's a lovely little Jet Airplane!

It's hard to say, I barly notice it. And your right to say it's a lovely little Jet, because it seems so. There usually on there landing approach, reasonably low and very quiet. The runway is to my north, across the Hwy, less than 3/4 mile away. The Minnesota Air Gaurd (148th) is also there, and I see a whole lot more F-16s everyday. Lots of C-130's out of the Twin Citys- practicing touch -and-goes. Occasionaly other stray warbids drop by, too!

Thanks, and good luck on your build! What's it modeled on? and how big?


It's after the Aviation Design E-Scorpion, most of what you ask is in firt post here: https://www.rcgroups.com/forums/show....php?t=1819176
Jul 07, 2013, 10:02 AM
Learning to make
Thread OP
Looks very cool!
So sorry to read that you had a Stroke.
What is it about the E-Scorpion that makes it so heavy for size??

About the Vision SF50, nice to hear that it's quiet for it's size, I didn't know that!(But it's probably useless to try make mine have scale sounding noise, LOL!)
I wonder how to make the Fuselage? I want to make it look perfectly scale,(Hobby quality!) know any construction methods?
At the time of writing I will only have EPP sheets 3-20mm thickness and Geldipac 3mm Sheets available to make the Airframe with.
Last edited by fossil1999; Jul 07, 2013 at 11:48 AM. Reason: Forgot a word
Jul 07, 2013, 11:53 AM
Learning to make
Thread OP
I found this thread on bending Depron, do you think it will work on EPP???
https://www.rcgroups.com/forums/show....php?t=1079598

P.S Also, if Retracts are too heavy, would omitting them and belly-landing the plane instead hurt it?
Last edited by fossil1999; Jul 07, 2013 at 11:59 AM. Reason: P.S
Jul 07, 2013, 12:52 PM
Registered User
D_FAST's Avatar
Built a few of GGRN designs,

Depends on what best suits you. Some carve, some use bulkheads and skins

Many of us belly land, some use epoxy and glass, some use tape, some use silkspan and wbpu or glass and wbpu to toughen them up, but this also adds weight.

You'll first need to start with good 3 view drawings and stations would be a bonus.
Jul 07, 2013, 01:20 PM
Learning to make
Thread OP
Quote:
Originally Posted by D_FAST
Built a few of GGRN designs,

Depends on what best suits you. Some carve, some use bulkheads and skins

Many of us belly land, some use epoxy and glass, some use tape, some use silkspan and wbpu or glass and wbpu to toughen them up, but this also adds weight.

You'll first need to start with good 3 view drawings and stations would be a bonus.
Thanks!
I found this EDF at Hobby king, people say the specs are wrong and that it's more powerful than the specs say it is:
https://www.hobbyking.com/hobbyking/s...Assembled.html
Looks like an ok EDF, but I'm very open to suggestions!
Jul 07, 2013, 02:24 PM
Learning to make
Thread OP
Found a three view Picture, looks like it will do after a bit of photoshop treatment!
http://www.cirrusaircraft.com/static...n/geometry.jpg

P.S Looking from the pic it looks like the SF50 has positive dihedral, YAY!
Last edited by fossil1999; Jul 07, 2013 at 02:36 PM.
Jul 07, 2013, 02:37 PM
Do it Right, the first time!
CoolerByTheLake's Avatar
Found a few things for you.
Videos

http://www.cirrusworld.com/tags/vision/

There is another view similar to this one, but I haven't found a large enough one.. This one took a couple of hrs off and on.

Looks like you beat me to it!!

http://www.bing.com/images/search?q=...ages&FORM=IGRE
Last edited by CoolerByTheLake; Jul 07, 2013 at 02:49 PM.
Jul 07, 2013, 02:48 PM
Learning to make
Thread OP
Well, at least two people knew about the pic before it was posted here! (you and me! )
So if I use Adobe Photoshop to add some rulers on the pic, It should work!
Thanks for the videos, I didn't see them!
Jul 07, 2013, 03:20 PM
Do it Right, the first time!
CoolerByTheLake's Avatar
What I did on the Scorpion, was to take the separate views--side only, top only, etc, . I made several copies in a file, so I could disect them into top and side view. Once you crop a photo and save it ,the original is toast!! Printed them out, made them into PDF files, and enlarge them in Adobe Reader. That gave me the scale that I wanted. A little trial and error involved---Have lots of ink for your printer!!

I think first I may have figured out the scale. Metric is not my stong suit, but used it anyway. In my case I converted , lets say total fuse length from mm to inches. Used this one: http://www.towerhobbies.com/help/convcalcs.html

As you probaly already use metric, print out the photo you have, measure total fuse length, take that number and divide it into what you think you want for length on your model. I measured the in the photo, and on my screen got 132mm =5.1968" Lets say you wanted a fuse length of 35", divide that by 5.1968=6.7349--That's the multipling factor any length measured will be X that number. Do the same for width, it may not be the same number.

Or just go by reducing the scale. Real one is 29.6ft/9.02m Same 35" model scale would 10.114 to 1

I used the first method, as I wanted a certain size and wasn't worried about what scale it was---There is no real Scorpion! Who will know!


2010 Duluth Air Show: Cirrus Vision SF50 (Jet) (2 min 20 sec)

Here's one, I missed that air show, just watched the Blue Angles from my back yard. In fact the Friday before the show, they flew directly over my house at about 500ft. All of them! Hell-of-a way to get woken up in the AM.

This is the matching photo to the one we both found. It is so small!! If where you got the first one, maybe they have this, just BIGGER!
Last edited by CoolerByTheLake; Jul 07, 2013 at 03:39 PM.
Jul 07, 2013, 03:39 PM
Registered User
Quote:
Originally Posted by fossil1999
Thanks!
I found this EDF at Hobby king, people say the specs are wrong and that it's more powerful than the specs say it is:
https://www.hobbyking.com/hobbyking/s...Assembled.html
Looks like an ok EDF, but I'm very open to suggestions!
Perhaps you missread ? It's not well reviewed at all.


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