Converting 2-seater to 4-seater?

Thanks for the reply! Can a kit-plane like Sling 2 kit be modified and applied for Experimental Certificate?

One important fact I missed in my calculation is the fuel load. The useful load of 696 lbs also includes fuel. The full-tank fuel load on a Sling 2 would be about 245 lbs and it totally messes up my calculation! I might still be able to carry four of us, but I won't be left with any allowance for the parachute.

 

Thanks! Yep, the structural strength of the airframe would definitely be an important factor to consider while installing the seats. And yes, I did realize that I did not include the fuel load.

A 4-seater kit (Sling or Van's) are almost twice as expensive as their 2-seater kits and that places 4-seaters in an unreachable territory. 2-seater kits in 2023 are about $110K, which is the price of a luxury car. Some down and some loan makes 2-seaters somewhat affordable (though tight, still somewhat affordable) for normal people like me.

 

It's a kit airplane. It has to be certified as either an E-LSA or E-AB which are both experimental types of Air Worthiness Certification. Based upon what you're asking to do E-LSA is out for a number of reasons. So that leaves E-AB under which you could mod the design to your heart's desire. But the issue is most kit aircraft don't come with engineering drawings, but rather assembly instructions. This could make it more difficult to safely make a major alteration to the basic design. I strongly recommend not going down this path if you aren't an engineer and/or have no experience building.

 

Thanks for your input! Even though I hold an engineering degree and understand basic to advanced concepts of physics, I am inclining towards getting a 2-seater kit and not modify it at all.

I am glad I could get some replies from a 5 year old thread. Thanks all!

 

You can get something already flying for significantly less as long as you don't need a designer label airplane like a Vans.

Wittman Tailwind, T-18, etc., etc., etc.

 

And unless you're wedded to E-AB (either building or buying already flying), a used standard certificated aircraft (eg 172, Cherokee/Archer, etc) certainly meets your requirements. You really need to take a hard look at your mission and what's available to meet it. Building is an endeavor not to be taken lightly, even with today's modern kits -- you need to approach it as a journey you're interested in taking and not as some inexpensive path to aircraft ownership.

 

The only LSA I know of where this might be physically (but probably not legally) possible is the Jabiru J230. https://en.m.wikipedia.org/wiki/Jabiru_J230 The 230 uses the same wings and fuselage as the 430, which is a 4-seater.

Essentially, Jabiru removes the rear seats and placards the plane to LSA limits. But I don’t know how you could convert a 230 into a 430 and comply with regs.

 

Converting 2-seater to 4-seater?
Simple, follow the airlines lead on this; remove the 2 seats and replace them with 4 seats half as big as the 2 you removed.

 

Don’t forget people frequently get heavier as they age

Your 80 lb children will be 120 by the time you finish building your plane

 

Thanks! Yes, Jabiru 430 kit could be a good options for my use case. I am going to try and find out if Jabiru 430 can be fitted with a Rotax 914 UL. Jabiru 3300 6-cylinder does not have the most reliable track record, outputs 120hp and weighs dry at about 185 lbs, where as Rotax 914 UL produces 115 hp but weighs only 142 lbs. Jabiru 430 kit already comes with a wooden-composite so no weight savings there.

 

This is not a bad idea at all, every ounce counts when you are trying to lift yourself in the air!

 

Agree! This fact should also be in consideration while dealing with months long assembly time. However, my second 80 lbs is only a year old and not 80 lbs at all at this time! But again, this conversion seems out of question at this point after doing some further research and going thru the opinions provided here on this thread. Nothing is impossible but it boils down to how much time is worth spending going thru all those difficult steps, especially getting any-category air worthiness certificate to get it in the air legally.

 

Good answer

 

Months long, with little kids. I almost spit my drink out over my keyboard at that one. Good luck with that. I would caution against being overly optimistic on the time required to build. Typically, it's usually longer, in some cases much longer, than the builder anticipates and that's if you stick to a stock build with no significant mods added in. Life, especially with kids, has a habit of getting in the way. Also don't rely on kit manufacturer projections -- they are often generic. Find a builders' forum for the make/model you want to build and get data from actual builders.

 

Since we’re reviving the thread, I’ll just add a factory conversion…
https://en.wikipedia.org/wiki/Thruxton_Jackaroo

 

Reminds me of the 4 seat BT-13 conversions after WWII

 

Hadn’t heard of them…got any links to info?

 

http://www.warbirdinformationexchange.org/phpBB3/viewtopic.php?f=3&t=10838

If you can get the link to load, it looks like a poor man’s Spartan Executive

 

You could add the child seat to the back of a 150/152. Not sure if that gives you 3 or 4 seats though.

https://avfab.com/products/view/cessna-150-152-child-seat-auxillary/