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Thread: any aviation experts/enthusiasts here?

  1. #11

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    the biggest challenge right now is getting the engine and all the remaining moving parts. i just can't find anyone who'd sell me just the engine without the rest of the machine
    Gracious. Learning flight is something I've procrastinated away for the past 40 years. But I did find out from my grandpa a couple of engineering headaches... one is that the Wankel engine was made first for the Luftwaffe and... resizing solid components is a real female dog. Later I found that Wankel motors could come to the States In A Mazda or in a model aircraft kit and now even the latter is on hold. Because it's made in China. The EU refuses Mazda because of the German patent, and the Chinese versions are not very welcome in the West. Except, perhaps, Mexico. They don't care about EU patent laws. Next best is Yamaha makes a racing dirt bike, 2 cycle, you can swap the top-end from 350cc all the way to 650cc without destroying the center of gravity. I've been working on that to motorize another bicycle. Here in Colorado you can have a 49cc motor without a license. for bikes of any kind...but nobody actually checks. Non-standard vehicles is a passion of mine. Also the FAA now wants to license drones, and already have licensing issues with ultra-light fixed wings and gyrocopter craft... And with all the military bases around the Air Farts have a lot of regulations. No Fly Zones. Even hang glider use has restrictions. I'm rooting for you.

  2. #12

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    wankel engine is completely out of the question for this project. i just don't have the budget to buy a whole car just to get the engine. besides, mazda RX-8 is a damn nice car so i really wouldn't want to dismantle it.

    anyway, i just remembered that my dad's car mechanic is also an aircraft mechanic and a helicopter pilot which means he definitely knows how to get the stuff i need. we're seeing him next week so maybe i'll finally make some real progress on this project. i'll certainly post some pictures once i move from the drawing board to the workbench

  3. #13
    Musashi

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    I've only had 3 or 4 hours of flying a Cessna 172. It was stall training.

    However I prefer to fly in x-plane, that's where I learned some autopilot rf landing through the uk dude on youtube.

  4. #14

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    Quote Originally Posted by Alexia View Post
    that's why pre built kits are not an option here. i want to use my own design with a fully enclosed cockpit and yoke control. it's all part of the challenge that i set for myself.
    I know a lot of guys (they've all been guys) who built their own planes. Including the guys who designed and built SpaceShipOne. All of them started with kits. Every single one.

    The questions you're asking here suggest you're not ready to design and build a plane, frankly. For instance, horsepower. The plane I fly has a 5.9L 200-horsepower Lycoming IO-360. That's 200HP at sea level. By the time I hit 12,500' I'm lucky to make ~55% of that power, spinning my two-blade scimitar prop at 2700 rpm (for climb, but leveled off, probably closer to 2500 depending on the mission). And yeah, once the propellor tips go transonic (which isn't exactly RPM-specific, but a function of length + RPM; most GA planes are using 74" props which have an effective operating range up to around 2700 rpm, some engines (Continental IO-360-ES) are spec'd to run to 2800, which might work if you're spinning a smaller, multi-blade prop...), the prop's efficiency drops precipitously, because it's basically doing nothing but churning the air.

    You asked why a smaller engine couldn't spin a prop with a gear box. They do. The Rotax engines (912, 914, etc) do just that, operating in the 4700+ RPM range but turning a prop around 2500 rpm. But that's more noise, more vibration, more maintenance, more weight, etc. So most planes don't use a gear box. Cessna tried combining a traditional aircraft engine with a gear reduction box on the 177, and it was kind of a disaster (though a lot of that was pilot error).

    Anyway. I digress. For your first effort, pick up the plans for a KR2 or somesuch and get to building. Get an engine meant for aviation purposes. Do it right. Learn a lot. There's always time enough to build your own plane, when you understand fluid dynamics properly, etc.

    Oh, and, AircraftSpruce is your friend. I make a pilgrimage there regularly (they have a shuttle that will pick you up from Corona Airport).

  5. #15

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    Also:

    http://www.redddit.com/r/homebuilt

    Here's an RV-7 that broke up mid-air because it's highly experienced ATP certificates pilot exceeded the Va speed; how will you determine the safe maneuvering, etc speeds of your bespoke design? https://generalaviationnews.com/2017...s-up-inflight/

    And, look at all the service bulletins from Vans on their ubiquitous, professionally designed, homebuilts: https://www.vansaircraft.com/public/service-rv7.htm

    This stuff ain't as simple as it looks...

  6. #16

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    Quote Originally Posted by WildBlueCrinkle View Post
    Also:

    http://www.redddit.com/r/homebuilt

    Here's an RV-7 that broke up mid-air because it's highly experienced ATP certificates pilot exceeded the Va speed; how will you determine the safe maneuvering, etc speeds of your bespoke design? https://generalaviationnews.com/2017...s-up-inflight/

    And, look at all the service bulletins from Vans on their ubiquitous, professionally designed, homebuilts: https://www.vansaircraft.com/public/service-rv7.htm

    This stuff ain't as simple as it looks...
    Agreed, actual airplanes are not only far more expensive, they are that more dangerous as well. Hence why I keep on recommending Alexa shoud try building an ultralight.

  7. #17

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    as i already said, i can't afford a kit and/or a proper engine. i also know enough about structural integrity to design a frame that won't collapse under load so there's no need to doubt my abilities. but a sturdy frame is still just a brick without the engine and that's why i'm kinda at the point where i feel like giving up.

    the only option i see here is to forget about the engine and a proper cockpit, increase the wing area, and end up with a glider that i'd launch from a nearby hill. that'd be extremely lame compared to my inital plan but it seems like it's the best i can do in this situation.
    but then again, even the Wright brothers built a few gliders before their motorized prototype was ready. i could probably still bolt a couple of chainsaw engines on it and see if they have enough power to do anything useful

  8. #18

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    Quote Originally Posted by Alexia View Post
    ....even the Wright brothers built a few gliders before their motorized prototype was ready.
    The Wright's Flyer was launched by catapult, ultimately destroying the airframe, so you need to factor in the cost of that, if you're using the Wrights as your sole inspiration.
    Also, the oft quoted $1000 cost of The Flyer is over $28k in today's money (keeping in mind that the Wrights had their own factory and craftsmen and engineers in their employ); a 1978 reproduction from the original plans cost over $11k in today's money.

    The cost of a modern kit compares favourably with the cost of The Flyer. Mark Evans' A Plane is Born, available on YouTube, goes through that process (his helicopter one is also worth watching).

    I'd planned another reply, few days ago, but wasn't sure if you weren't still sore from all the other negative replies, and at that time saw that a Rotax 447 and a suitable propeller were available on eBay for a total cost of around $900.
    Not sure if the engine was just bare-bones or included fuelling and electrical systems.
    Props are readily available from the US, sourced mainly as old barnstormer parts turned into decorative ornaments. Whether they'd be airworthy or not is another matter.
    On a similar airworthiness note, any land engine will need to be made airworthy, probably running into hundreds of dollars to make so.

    You said originally that the numbers add up, but of the numbers that you've so far provided, they don't.
    Obviously, I don't want to kick you while still down [about this], but I still do think that you need to have a rethink about the project.
    And we've not even got onto construction methods and materials; btw, Wikipedia's page on the dehavilland Mosquito goes into a fair amount of detail about wooden airframe construction.

    And with my earlier hint of radio control, I wasn't talking about a scale model, just more of not wanting to hear about you burning to death at the bottom of some field.

  9. #19

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    Quote Originally Posted by Alexia View Post
    i also know enough about structural integrity to design a frame that won't collapse under load so there's no need to doubt my abilities.
    I think (for those of us that have formal training and experience with this/engineering) this is what makes us uneasy. It makes me uneasy. You haven't really shown much proof of understanding static or dynamic loads, much less anything to do with power transmission. You could help all of us by sharing your plans? Show us your idea, show us your design and planned building materials.

  10. #20

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    i never intended to replicate the Wright flyer. it's a terrible design. i just thought that if they could build a flying machine all the way back in 1903 i should be able to do the same since i have a lot of better materials available.

    as i already said, any rotax engine is completely out of the question for this project. if i had the funds for it i wouldn't even be writing here right now.
    i kinda already gave up every last bit of hope to build something that'll take off under its own power so i'm going with something that i'll launch from a hill. i would make it remote controlled but i thought i already made it clear that i can't afford it.



    Quote Originally Posted by Llayden View Post
    You could help all of us by sharing your plans? Show us your idea, show us your design and planned building materials.
    i don't have any drawn plans so far. the whole design will completely depend on the engine i'll end up getting and i currently have no idea what that'll be. my plan is basically to first get the engine then build the whole thing around it.

    however, i do know what kind of materials i'll use. assuming i'll get a heavily underpowered engine i'm planning to use plywood or pvc tubing and foam boards for the sake of weight reduction. since i won't have anywhere near enough power to do a barrel roll or anything else that'd stress the frame i'm very confident it's all gonna hold together

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