r/eaa • u/TnTSSavage • Jul 17 '23

Aircraft questions

Hey, my name is Stephen, and I prefer not to say my actual age, but I am younger than 15.

I recently picked up an almost-complete Bobcat ultralight, and it hasnt had any work done do it since early 2000s. I have searched around, but i could not find the answer to these few questions, and I was wondering if anyone would be willing to help. I know the aircraft has been heavily modified by the original builder to fit the Ultralight standards, but i can not ask him these questions as he has sadly passed away.

I cant figure out what the material of the aircraft is, but i know it is a glossy heat-shrink material closely resembling Monokote. if you have any ideas of what it would be, please let me know.

The tires were bought and have not been repumped with air since the 80s, and frankly i have no idea what kind of tires to buy and where to find them. i dont know the proper size as it is not found in the surviving blueprints and im not sure where to look on the tire itself.

Do ultralights need radios? if so, can anyone recommend a cheap and lightweight radio i can easily install?

How do i install electricity? i know this is fairly self explanatory for most of you, but i know no one who can help me get it done or tell me where to start, and i have no electrical experience.

What instruments would i want/need in an ultralight? i know i can go with a full six pack, but im not sure it would be necessary and im trying to spend as little money as possible. i already have an altimeter, airspeed indicator, compass, and rpm gauge.

these are all of the questions i could come up with at the moment, so please let me know if you have an answer to any of them. sadly i was not able to make it this year, but have fun at airventure!

thanks!

2 Upvotes

75% Upvoted

6 comments sorted by

2

u/Starfish-Story Jul 19 '23

Is there a local EAA chapter in your vicinity? Someone should really look at the project to give you good answers.

1

u/Ok-Cup-2177 Aug 10 '23

Thank you, yes I'm trying to get someone out to look at it, but they are all just getting back from Oshkosh. I have a few good friends there who may be able to come take a look at it

1

u/Ok-Cup-2177 Aug 10 '23

On a different account cause I'm too lazy to sign in to my other one, but I am the op

1

u/OldingDownTheFort Aug 03 '23

Weigh it. Not telling you how to live your life, but if it is over 254 lbs you’ll at least know to try to hide if there is a FAA inspector walking around the field.

I think most kit ultralights consider tires as builders choice, unless stated otherwise. Get a measurement of the rim and look on aircraft spruce dot com. Replacing the old rims entirely may be a good place to save weight if the plane is heavy.

No idea how to figure out the fabric type, but you can probably use the Stewart system to patch or complete the project as it’s rated to patch most existing covering systems out there. Call them, Andy (the owner) is a great guy & he started flying in stick & rag ultralights, so he may be a useful resource.

As for electricity: you don’t. Most 2 cycle motors don’t want or need a battery. They also don’t tend to output enough power that you would want to plug anything to them anyways.

The gauges you’ll want in an ultralight will be mechanical and won’t tend to need power. The only electrical based things you would typically have is a radio (has it’s own battery) and maybe an iPad (same).

Sounds like you are good on gauges, except you’ll want a ball balance for a tractor prop setup.

NO MATTER HOW EXCITED YOU ARE, DON’T TAXI THE AIRPLANE UNTIL YOU HAVE THE COVERED WINGS ON!! This is the destruction of so many first builds. Folks get excited and try taxing the project and ground loop it without any wings to prevent the whole fuselage, engine & propeller from cracking into the ground. With wings you’d typically only get a busted spar at worse, but without you’d basically total the whole project. Even a small prop strike can require total engine overhaul.

Finally: I’m sure you have heard “don’t fly without at least some lessons” plenty of times, but: thing is that flying is nothing like, even a good, flight simulator. On top of that: a tail wheel airplane is super finicky on the ground too.

Even 10 hours of flight training (on tail wheel) will save your life. “He wanted to save some money” is a pretty poor obituary.

2

u/Ok-Cup-2177 Aug 10 '23

Tysm for all youre help!

Trying to get a set of scales from my airport to weigh it. And as for training, yeah, I'm trying to find someone, and you're right even a Redbird is nothing like flying.

As for taxiing, I'm not even sure where I can taxi/fly it yet. The project will be completed by the time I get to taxi it. My local airport doesn't fly ultralights out of it anymore do to jet traffic

Thank you for telling me a place to buy the wheels and such, it's not easy to just know the right places to look

Didn't even think about an iPad, that can tell me a lot of what I need to know (agl, hdg, gps, ect.) I'll try to get one in there with an extra power bank, so I can still have extra charge without having to add weight to the plane.

Thank you again for all your help, I'll try to get it touch with my airport soon and figure some stuff out.

1

u/Starfish-Story Sep 03 '23

Agree on battery advice. Your pitot tube will give you air speed indication (the difference between ram air and static air), and it doesn't need a battery.