First of all Corona Virus Covid19 sucks.

Its been a long time since I have added anything to my blog.
I have gotten into 3D Printing and have acquired a Creality Ender 3 Pro for my birthday.
The Printer is a neat little machine, when I got it the printer had a little problem with under extruding and found that the firmware had a variable that needed to be set to off (https://www.rcgroups.com/forums/show...9&postcount=14).
This fixed the printer problems and now have it tuned to build real nice thin wall ABS.

I am keeping some updates on this thread so I can get input on how do things like modeling, slicing the model into convenient part etc:
https://www.rcgroups.com/forums/show...h-American-FJ1

I acquired an FMS/ROC P51 Strega from the Hobby Shop in Sugarland last weekend. The kit is simple to assemble and even I could assemble it in a couple afternoons. The only problem has been one of the aileron servos was bad with a hitch at center. I replaced the servo and it seems the servo now operates opposite to the one I replaced. I know all the servos I keep as spares all operate in the same direction I can only think that one of the servos are reversed so they operate on a simple splitter. I may need to go straight to the receiver and work a mix to get the desired directions on the ailerons.
Everything else works perfectly.

Well another one that I wanted to start has begun.
I started cutting foam on D-Fasts Scorpion.

https://www.rcgroups.com/forums/show...43&postcount=1

This is one I wish I could afford in 90-100mm size, but Dan has captured it and I will endeavor to build it...

Thanks Dan, now if you get that A4 or the F4D done I will get them to build as time goes along...

Cheers,
Eric B.

I received the files to cut and build an F106 in the Scratchbuilt EDF forum.

https://www.rcgroups.com/forums/show....php?t=1722906

I will cut the templates and then assemble it, I hope I can do a decent job. I will give a rundown of how I expect to build and finish it in the next few days after I retread the thread and go over the plan in more detail.

Cheers,
Eric B.

Several years back Orlando and I made a T2A for 50mm fans.

https://www.rcgroups.com/forums/show...00#post5514048

I lost everything on an old laptop and only had a few files on a removable hard drive and after some discussions with a few people I decided to try to redesign it in DevFusFoam. The results came out really well but after having some problems with not having AutoCAD or Dev CAD to detail wing placement etc, I took th old files and reworked them at before work and at lunch to get some real drawings I could cut a couple from.

Here is a couple of pictures from the model and it is done in Inventor 2013. I expect to have the drawings to cut the parts sometimes next week.

The statistics are as of this moment:
Winspan: 44.5in
Length: 47in
Wing Area: 430in^2
Projected Weight: 3lbs
Wing Loading: 17oz/ft^2+

Looks like I will have a busy fall and winter this year.
More to come...

Cheers,
Eric B.

To preface this blog entry, I started on a on an AN72 several years back, but lost the last update of the files to a hard drive failure before I could back up to an external drive. I lost a lot of work on the interior crutch system. I had redesigned it to be a framed stick crutch system like the way some air frames for free flight are designed with the foam sections held onto this crutch. The reasoning there to make it strong which I could control by going larger or smaller in stick cross section. Lots of design and should have been pretty easy to build. But it was gone and I did not have a CAD system I could easily rebuild it with so I shelved the older files and closed the design. I was given a 1/72 metal model of the AN124 in Volga Dnepr from the guys in shipping at work to build one in their company colors of the model, we use the company for shipping some of the equipment we make to different parts of the world when needed also known as "we are late and have to get it there on time"...
So this blog entry is the design and build of the AN124, 4-70mm fans. The preliminary physical sizing will be 106" WS, 94" LG, 10lb flight weight.
More to come...

Well what can I say its been a long time since I was able to work on this 3D model.
Its pretty raw but at the time i figured that I would be able to work on it again. After loosing a couple of old laptops with all my old cad programs on it I cant work on it any more than it is ATM. I decided to take the sections I had made for it and go ahead and build the plane. I had always wanted one.

After seeing Keith Sparks C130 https://www.rcgroups.com/forums/show...highlight=c130 a few months back and a few of D-fasts projects https://www.rcgroups.com/forums/show...0#post22957750 and Uncle Crash's project https://www.rcgroups.com/forums/show....php?t=1719658 I decided now is as good a time as any to start. Unfortunately I am not the modeler these guys are, just trying to have fun and keep learning...

I have a CNC machine but alas it is down because I am too cheap to buy a monitor for the old desktop that drives it so it wont be used. I did make up a few tools to cut the foam by hand that I found in Keith Sparks book "Building with Foam" - http://parkflyerplastics.com/cart/in...roducts_id=644.

The templates were made from heavy poster board and they work well enough but I think I will have to recut some of the parts over as I reclaim skills I have not used in a long time, I cut some parts of the fuselage over the last few days and it sorta looks like what I modeled..

I will post some pictures of the build tomorrow along with some pictures of the drawings/models. Here is a link to some of the pictures I had made of the 3d modeling. Pictures start on post 32 to 45 https://www.rcgroups.com/forums/show...5&postcount=45

Cheers,
Eric B.

Several months back I lost the usage of my CAD programs I had been using for several years when my old laptops hard drive died.
I lost a lot of modeling - arround 10 years worth to be exact. Now I still have the files just not a program that can read them.
I have since gotten a new laptop and found a few CAD programs that work surprisingly well and are easy to use.
I had been using AutoCad v2000 and Inventor v5, inventor was used to make 3d models and AutoCad was used to prep the 2d parts derived from the inventor models for use in my cnc machine.
The programs I have now are DevFusFoam and will soon be getting DevFusCam for wood modeling. I plan to get DevCadPro for general drafting and ProfiliPro for wood\foam wings. Each will generate g-code to run cnc machines which is a big plus.

Link to DevCad products: http://www.devcad.com/eng/devfus_frame.htm

More to come...

I am continuing my discussion here on this thread.

GWS 40mm/2018 5800

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This 40mm fan/20mm motor combination seems to be at the stores.

http://www.caliberhobby.com/df_edf40.html

This should make a lot fo power available to small airframes, the cost will be a little more weight from a little larger battery but the performance promisses to be well worth the extra weight.
Common 12mm fans wont make the thrust this one is capable of because the 12mm motor is not capable of producing enough torque to work with the higher thrust the fan is capable of.

Numbers from GWS testing:

14.8volts, 26.5amps, 392watts, 413gr, thrust, 14.57oz thrust

I bought one to try in the F86D which lost a bearing a couple weeks back. If it works I will get more, 40mm is the perfect schoolyard/park jet at least for me.

Eric B.

Well after a computer hard drive crash that took the last files I had started, I have just about everything loaded back on the new one and here is my first project. This will be a 40mm fan driven model. My goal is to reach the highest speed I can design/build and fly in this small model. I have entered the stock 40mm class with a GWS 40mm 20mm 5800kv and 4s. Here is what I have so far.

Eric B.

Several years back when the X32 and X35 were going head to head for the nextgen lightweight fighter, Kevin Cox designed and built one for 50mm microfan. I lusted after that plane...

A couple years back I tried my hand at one and almost had it flying for the GWS40mm fan with a Feigao bl motor on 3s. The airframe needed to be a little larger as the wing loading on a flat plate airfoil was too small(~100in^2) and too touchy for my reflexes. a few months back I thought about trying again and using a larger airframe (~225in^2) and a 50mm microfan.

This is the thread for my design, build and test flights after which the plans will be available to anyone who wishes to download and build as long as its not for profit.

This is as far as I have gotten with the design to this point. I am involved with another project that is undergoing some changes and until that one is complete I wont do much on this one.

Eric B.

I have always been drawn to this aircraft, very interesting layout and not modeled much if any.

So I decided to do one for myself. Since I have a hot wire CNC I will use it to make the parts from foam. So it begins...

To fill in a little of its history:

The Antonov An-72 (NATO reporting name 'Coaler') is a transport aircraft developed by Antonov in the former Soviet Union. It was designed as a STOL transport and intended as a replacement for the Antonov An-26, but variants have found success as commercial freighters.

The An-72 first flew on 22 December 1977. Produced in tandem with the An-72, the An-74 variant adds the ability to operate in harsh weather conditions in polar regions, because it can be fitted with Wheel-skis landing gear, de-icing equipment, and a number of other upgrades allowing the aircraft to support operations in Arctic or Antarctic environments. Other An-72 versions include the An-72S VIP transport and An-72P maritime patrol aircraft.

An unusual design feature of the An-72 and An-74 is the use of the Coandă effect to improve STOL performance, utilizing engine exhaust gases blown over the wing's upper surface to boost lift. The first flight was made in August 31, 1977, but it was only in the 1980s that production started. The power plant used is the Lotarev D-36 turbofan engine. The An-72 bears a resemblance to the Boeing YC-14, a prototype design from the early 1970s which had also used overwing engines and the Coandă effect.

The rear fuselage of the airplane has a hinged loading ramp with a rear fairing that slides backwards and up to clear the opening. Up to 7.5 tons can be airdropped whilst there are folding side seats for 52 passengers.

The An-72 has extremely good short field capabilities. Like many other Soviet-built aircraft, this jet plane was designed to operate on rugged airfields, its powerful undercarriage dealing well with sand, grass or other unpaved surfaces.

Well Stay tuned for construction and flying.

One thing that I have run into many times is calculating fan performance for determining motor specifications. This is a spreadsheet that I took from a larger sheet that I use to work on a lot of my fan models. The idea is to get enough information to determine as close as possible the Kv of a motor to be used in the fan with a competent prediction of performance and power needs.

I welcome feedback from users.

Now the disclaimer is this spreadsheet is for personal use only, I am not responsible on how it might be used or understood as there are a lot of variables that can be tweaked to get an answer that wont be useful in reality.

Eric B.

Part of the hobby for me because of what I do for work (mechanical designer) is to design my airplanes in CAD. I use two programs, Autodesk AutoCAD and Autodesk Inventor. I will start a new model on the thread tonight. The airframe I have chosen to model is the ME P1092/2, my inspiration came from watching a friend who designed his own model of the /25 model. I chose this variant because of the straight thru inlet to outlet.
I will make installment updates as I make progress.

Cheers,
Eric B.

What do you think of this?

This naccelle was designed arround the GWS 40mm fan and GGRN's A310, I can scale it for any size fan available if there is interest. I will finish this one out in the next few days and see what I can get out of it...

Eric B.

I entered a contest in the Foamy EDF forum to develop an airframe of choice for micro EDF fans ranging from 30mm to 40mm. I chose 40mm and this will document the design and build of the little sport jet. More to come...

Well here is a little more.

Some pictures from my AutoCAd design, it orriginally started as a schoolyard sport plane using my Alfa fan and LSJS. I scaled it for the 40mm fan and added a little wing area.