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Old Dec 26, 2013, 12:24 PM
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FPV Jet Budget?

I am thinking about delving into RC jets. I have played around with regular electric RC prop planes before, but my main interest is in electronics and software, in which I believe I am capable of the electronics and software I describe. I am considering making it my project to work on a miniature jet that:
1. ...can fly at 300 mph or more.
2. ...can switch from manual FPV flight to GPS-based autopilot and vice versa.
3. ...can fly for a range of at least 20 miles (and back).
4. ...has a wingspan of less than 1 yard.
5. ...has an entirely custom-built miniature jet engine.

I would construct the shell of the plane out of a 3D-printed material consisting of aluminum dust suspended inside of hardened nylon. The jet engine would be machined from medium-carbon steel. The control surfaces would be controlled by a miniature servo-based hydraulics system. The autopilot and software would be based off of the Atmega328 microcontroller (Arduino UNO). The engine would burn butyl alcohol, or butanol. It is very similar to gasoline. I realize that this is not a reasonable goal, but is it possible? I am setting my max budget at 2,000 USD. Is that reasonable?
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Old Dec 26, 2013, 05:48 PM
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Quote:
Originally Posted by VarietyBook View Post
I am thinking about delving into RC jets. I have played around with regular electric RC prop planes before, but my main interest is in electronics and software, in which I believe I am capable of the electronics and software I describe. I am considering making it my project to work on a miniature jet that:
1. ...can fly at 300 mph or more.
2. ...can switch from manual FPV flight to GPS-based autopilot and vice versa.
3. ...can fly for a range of at least 20 miles (and back).
4. ...has a wingspan of less than 1 yard.
5. ...has an entirely custom-built miniature jet engine.

I would construct the shell of the plane out of a 3D-printed material consisting of aluminum dust suspended inside of hardened nylon. The jet engine would be machined from medium-carbon steel. The control surfaces would be controlled by a miniature servo-based hydraulics system. The autopilot and software would be based off of the Atmega328 microcontroller (Arduino UNO). The engine would burn butyl alcohol, or butanol. It is very similar to gasoline. I realize that this is not a reasonable goal, but is it possible? I am setting my max budget at 2,000 USD. Is that reasonable?
Impossible probably. The jet engine will suck down fuel. And your wing would be to small to actually carry all that fuel. Also 300 mph isn't something you just do. You have to keep on improving. You can't just build a great engine and jet on your first try. Don't spend all your money on a jet that would accomplish what you want. Maybe in the future you could make your own engine more effiecent and be able to go that 20 miles.. And what do you want to go 20 miles for?
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Old Dec 26, 2013, 09:42 PM
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Not possible at all.

I fly jets and am an electronic engineer.

An 8 bit RISC processor running at 20 MHz processing GPS data on a 300 mph airplane. I don't mean to be harsh but that is a complete joke. I wouldn't use 8 bit architecture for the engine. And neither do the current jet engine manufacturers. And you need to learn real coding...not arduino sketching. Great for the hobbyist, but lousy for real world operations.

Your engine alone will take 10 years of development. You best off using an off the shelf engine and that will blow your 2000 budget. And getting to 300 mph is not easy, even for jet veterans. It takes very specialized equipment and airframe.
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Old Dec 27, 2013, 03:22 AM
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To achieve this, or very near, you're looking at about 25K best case. Makes more sense to use commercially available gear + airframe, some modifications (more fuel capacity) will be necessary and best if you have this built and set-up by an experienced Jet modeler or perhaps a UAV professional - Cheers
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Old Dec 27, 2013, 08:17 AM
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OK... before I start... I love projects... but you are SO far off base, that you should stop now.


Before even answering your Q's.... what part of the world are you in? If you are in the USA... you can't exceed 200 mph, and turbine aircraft can only be "Line of sight". (GPS and FPV are not allowed)

Second thing is.... Unless you own a machine shop... you can't have any of that built for $2k. And that leads me to beleve this is another BS post. If you have read into any of the turbine model threads... you should know that. It's hard to buld a turbine model on all used parts for $2k, let alone all custom machined.

Lastly.... you can't build ANYTHING in a turbine out of "medium-carbon steel".



I'm smelling a Troll.
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Old Dec 27, 2013, 01:27 PM
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Turbines and 300 MPH airplanes are not for beginners. You have much to learn.
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Old Dec 28, 2013, 11:04 AM
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Thank you for the criticism (sincerely). It was really just musings and a dumb idea at that. I can't do anything related to this kind of super-RC-plane. I hate to suck up anyone's time in keeping this thread open, but is it possible for me to make my own RC miniature jet engine and plane at all (regardless of the foolish criteria listed above)? If so, what would you say is a reasonable budget (again, disregarding all of the unrealistic fancies)?
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Old Dec 28, 2013, 07:29 PM
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Ok, if you really want to build your own engine, Wren offer their first generation MW54 plans for free!!!

http://www.wrenturbines.co.uk/mw54-t...nd-stage-plans

You can also purchase the difficult to manufacture t-wheels and compressors from them as well. Keep in mind, you still need access to an engine lathe and knee mill to machine the necessary parts. Some of the mat'ls are also quite hard and you will need a budget for carbide drills and mills. HSS won't do the job.

I would also suggest joining the GTBA as there is a lot of information for home builders on the forums there.
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Old Dec 29, 2013, 12:27 PM
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Your idea sounds very much like a guided missile?
What benefit and why do you want to fly 300mph? Why do you want / would even think of using hydraulics on a small model with a small wing loading area?
On a lighter note, you can easily do a jet for 2000usd, look at second hand turbines on RCUniverse, eBay etc, build your own jet from plans, please don't just build something by eye and assume that it would fly, secondly have you ever flown a turbine jet before? They are in a different ball game, I fly several and even I still feel scared half the time, let alone going down the FPV route!
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Old Dec 29, 2013, 11:29 PM
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Believe me, this is no "guided missile." I had wanted to ignore all of the above fanciful criteria (20 mi and 300mph), as I was told those are not good goals. I just want to make a jet plane that is RC (and maybe FPV, too?). I want to break no laws. Well, maybe I can break a tiny law in order to fly FPV, but whatever. No other laws.
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Old Jan 07, 2014, 08:12 AM
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In the UK the Wattage output of an FPV device inc TX signal and AV feed should exceed no more than 10mw, I'm sure every other country has limits on this, if you were caught using such equipment you can get into lots of trouble ;-) rules are made to be broken but you have to use common sense. As a jet pilot I would advise you that it's very very very very very VERY hard to fly FPV at full throttle, you will be experiencing video lag which means your reaction will be out of sync with the aircraft by a fraction which on a jet will result in a very expensive lawn dart, you are also breaking the line of sight rule which i'm sure the AMA and the BMFA both regulate aswell as the FAA and CAA, build a high power ducted fan jet, I know we all have crazy ideas but for under $2000 you could get a lot for your money if you go down the electronic route. Remember fuel burn time in jets as well, my jetcat p120 will swallow a gallon in under 8 minutes at full throttle, while if you were do design a ducted fan hybrid glider you could easily fly for several hours.

I modified a Hobby king phoenix 2000 glider with a 4lbs thrust ducted fan, I can fly for a whole afternoon using a 3S 2200mah turnigy battery :-)
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Old Jan 14, 2014, 07:06 AM
310mph Kolibri T25 Swist
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Quote:
Originally Posted by VarietyBook View Post
Believe me, this is no "guided missile." I had wanted to ignore all of the above fanciful criteria (20 mi and 300mph), as I was told those are not good goals. I just want to make a jet plane that is RC (and maybe FPV, too?). I want to break no laws. Well, maybe I can break a tiny law in order to fly FPV, but whatever. No other laws.
Very fiew, even the pros fly at 300mph just because it's too fast for comfort. The fastest planes you can buy without going way outside the box are "just" sniffing 250mph and most really won't even hit 200mph.

Your plane would not be very plesant to fly RC or FPV, and a video link failure would easily lead to someone getting killed.

(I do fly 300mph, I know)
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Old Jan 14, 2014, 08:17 AM
310mph Kolibri T25 Swist
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So... what you are looking for must be a delta to handle the weight with that small wingspan. A Baiojet for example. I happen to know the turbine manufacturer so I got the most powerful version of the engine available, still only 235mph level flight...



Baiojet Kolibri T25, 375km/h (4 min 16 sec)


What do we do?? Find something with half the frontal area, wingspan increases but the plane are still "small", a Swist F5D racer.



Swist F5D, Pilots view - Jet Power Messe 2012 (2 min 38 sec)


Ok now we are lurking the 300mph mark with a little help from a dive, but there simply are NO room in the plane for anything, fueltank and electronics fill it all!! and only fuel for 3min.





What do we do... find a larger airframe, the all mighty 100% carbon Opus V-jet.

Ali Machinchy Opus Colt (2 min 10 sec)


But again we are slow, way off 300mph, tops 220-ish mph. What to do?? Massage the turbine builder to get even more powerful engines, and why not strap two of them on there while at it.



Is it faster? No it is not as the airframe + engines are too dragy. Are there room for anything else then fuel and ECU/batteries - NO! Even though we stripped the ECU from connectors and case and made a super slim install.








So just drop it and go fly foamies as you are way out of the envelope
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Old Jan 31, 2014, 06:14 AM
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"Is that reasonable?"

Come on guys, don't be so negative.

Sure it is. No problem. People do it every day. Home made engines, new airplane materials, formed by a new process, hydraulic controls, a little simple software, 300 mph, FPV and GPS, all in one plane. Finding the $2000 might be your biggest problem, the rest is child's play.
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