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StayQuiet's blog
Archive for February, 2012
Posted by StayQuiet | Feb 28, 2012 @ 12:20 PM | 2,442 Views
Whoops. The laser cutting table at the LHS can only handle a piece up to 24" long. Fuselage sides are longer than that. I'm going to have him cut out the wing ribs and some of the smaller parts that I'll need. The fuselage drawings were sent out to National Balsa Wood Co, who can handle it. I really didn't want to try to 'two piece and splice' the fuselage sides.

Did some research and found a motor equivalent to the E-Flite Power 15 from Heads Up RC, at about half the price. I picked up a 40 amp ESC and a 3s, 2200mah, 30C battery from them as well. Hard to beat their prices!

I want to give a "Thank You" to Scott Smith of Scorpion Racing, who helped me out with a CAD issue I was having.

It won't be long before I have a short kit and lots of balsa sticks in front of me, and the actual 'building' process can start. I have to admit, the sense of accomplishment I got from learning CAD (even though I still only have a rudimentary understanding of all the commands and features) and the planning involved in this build has been a lot of fun.
Posted by StayQuiet | Feb 26, 2012 @ 07:38 AM | 2,202 Views
Busy with ModelCAD. Stabilizer, elevators, fin, rudder, all the wing ribs have been drawn up. That's been the easy part, because it's all the same as the original plans.

Now comes the fun part: I have to start looking at the fuselage parts, and making the necessary design changes for battery access hatch, ventilation/cooling, and changing some of the fuselage formers (most notably F5) and adding in a cockpit floor in anticipation of the clear canopy.
Posted by StayQuiet | Feb 24, 2012 @ 08:40 PM | 2,082 Views
All parts for the wing that need to be laser cut are drawn up in ModelCAD. Tomorrow (hopefully) it's off to the LHS with files on a thumb drive to see if I can get them cut out. Oh, have to pick up some stock as well, just to get the wing build going.

Whiskers was kind enough to respond to one of my blogs about making a canopy out of a soda bottle. I may still try that, but in the meantime, I had enough material already laying around in my woodshop area to build a small (12" X 12") vacuum forming table, so the build cost me $0.00 - my budget likes that! Besides, the missus is very much into crafts, so I'm sure she will find a use for it as well - which justifies me putting a sheet of plastic in her oven - you know, just to show her how it's done.

Also been playing around with MotoCalc to get an idea of a power package for the plane. The original airframe weight is listed as 25oz, with a wing loading of 15.4oz/sq ft. Punching in the full weight, instead of a target, lighter one, I got a package using an E-Flite Power 15, 40 amp ESC, and 3s, 2100mah 20C battery. With that package added in, it computes out to 14.6 oz/sq.ft loading. According to MotoCalc opinion (how accurate is that?) it would make an ideal trainer for calm to light wind conditions, yet still have enough power for consecutive loops. So, I don't know how much weight I'll have to reduce (if any) on the build.
Posted by StayQuiet | Feb 23, 2012 @ 11:46 AM | 2,090 Views
First bits in CAD drawings are done. There are so many commands in ModelCAD, and I wish I knew how to use some of them. But, I just struggle along and it seems to get the job done (at least so far).

Now, as if ModelCAD doesn't keep me busy enough, I've begun to think that this plane would look much better with a plastic canopy, rather than the 'simulated' canopy made up of balsa sheeting. I've been checking YouTube videos on how to build a vacuum form table at home. Honey, why don't you go shopping, while I just warm up the oven?
Posted by StayQuiet | Feb 22, 2012 @ 06:23 PM | 2,007 Views
02/22/12 - just making a note for myself so I can see just how long this project is going to take me!

I looked over the plans this evening. Wing build is pretty straightforward, and I won't have to do any real alterations to the plan to complete the electric conversion. Fuselage looks like it has a nice area where the original fuel tank and receiver pack is located that can be adapted for a lipo pack, receiver, and ESC. Lots of weight reduction can be accomplished in the fuselage rear deck and tail feathers.

Step one: get some data points on the wing ribs and wingtips so I can enter them into ModelCAD. The easiest way I've found is to use a light table and some technial graph paper, which is laid out with grid lines 0.10" apart. By carefully tracing the outlines of the parts, I can then determine X-Y coordinates for points along the rib outline, and then use those points to re-draw the part in ModelCAD. I did remember to add in some building tabs on the ribs to help in the building process. Those tabs can be cut off easily after the wing is glued together. Those tabs aren't on the original plans.
Posted by StayQuiet | Feb 21, 2012 @ 08:23 PM | 2,110 Views
So here I am, looking at two sets of plans and possible projects.

On the one hand, I would really like to build a half sized "Double Impact", but that would entail a lot of re-scaling, and the thought of drawing multiple sized ribs in CAD (which I am still struggling with) just may turn into a study of frustration.

On the other hand, the "Demi Duster" is about the size I'm looking for (44" wingspan) and has a constant chord wing, so draw one rib up and just duplicate as needed.

The Demi Duster was also designed for glow power, and has a listed airframe weight of 25 oz. Looking over the plans and the build article (I got the back issue of Flying Models magazine when I ordered the plans) there are lots of areas on the airframe that could easily go on a diet. I think I can resonably get the weight down to around 18-20 oz and still have a pretty stout plane. Add in the fact that I'd need one less motor and ESC, and can use a smaller (re: less expensive) battery, and I think my decision has been made.

Tomorrow night, I start drawing up wing ribs in ModelCAD. It's a good thing I already don't have any hair, 'cuz I'd be pulling it out.
Posted by StayQuiet | Feb 21, 2012 @ 06:06 PM | 1,841 Views
Came home today, there's a long, triangular package waiting for me. Hmmm, what the heck is that?

Surprise! It's a set of plans for the Double Impact I had ordered from Carstens. So, what's the surprise? I ordered them on 2/3, and they arrived in less than three weeks. The last set of plans I ordered from them took over 3 months, and I had actually been told by Carstens that they had no record of me ever ordering from them.

Now, the bad news - the plans call for a tapered wing. My idea of redrawing the plans in ModelCAD at half size for electric power just got more difficult. Instead of drawing up one rib and duplicating it the required number of times, I now have multiple drawings to do.

Maybe I should scale down my idea....
Posted by StayQuiet | Feb 20, 2012 @ 05:27 AM | 1,575 Views
This may be a long, not often updated build log - just a warning!

For my winter project, I decided I would build a plane from plans - my first attempt at something like that. I found plans for a small glow plane (called the Demi Duster) through Carstens Plan Service, called and ordered them in November. My intention was to convert it to electric power.

Six weeks later, no plans. A call to Carstens to ask about my order got me a "we have no record of your order" response. Okay, I guess it happens. Hmmm, how about a twin? Carstens had plans for the Double Impact available. It's a large (72" wingspan) plane, designed for twin .40 - .51 glow power. A half sized version would be about perfect for electric power, and by scaling it down in ModelCAD I could get a short kit cut for myself. I placed another order with Carstens, this time on the website so I could get a copy printed out.

Two days later, the plans for the Demi Duster arrive. Three and a half months? Well, we'll see just how long it takes them this time. Order was placed on 2/3/12.

(By the way, I know the electric "Minimum Impact" is available. Just not interested in a quick foamie build.)