ea81 for model 3?

[yellow dart]

Hello wondering if i can mount an ea81 in my model 3 i have access to a nsi ea81 fwf kit,has anyone flown the 3 with this arrangement?also the kit is for a mod 4 classic,but i think the mount from the 3 to the 4 are the same?thanks,chris

[Mnflyer]

A very heavy engine for a model 3 too much wt up front.

[DBVZ]

I know someone with a Model 3, that I think has that engine. Let me check.

[wannafly]

avoid the tempation. I had one in my model IV and it is to heavey. Put the 912s in and double performance. That was my experience.

[SkyDave]

I have a Kitfox 3 with E81 built by Jack Bally featured in EAA 1993 mag. Great aircraft.

[SkyDave]

PS 100 pounds heavy than a 582 ???? what the 582 weight....62 pounds:confused:

[Peteohms]

That just about makes your III a single place doesn't it? My III with 912 is just barely a 2 place for slightly larger folks.

[SkyDave]

what do you weight 300 # ?aircraft @ 672# pilot @ 160# passenger @ 140 # can carry up to 26 gal of fuel but why fuel burn around 3.5 gph so to reach max weight add 13 gallons of gas (78#) or 3.7 hrs of flight... total weight 1050#... plane works great for me ...it is what it is ....personal plane to fit my needs cheap to fly...maintenance... park in my garage..and fun to fly

[DBVZ]

Glad you joined in. You gave the weight, but perhaps you could provide some performance numbers too. I think some of the concerns about weight are if the kit had 950 gross on the data plate instead of 1050. I think it is the Kitfox II that is 950 though. As a point if contrast, my Avid is empty weight 560 including the BRS; also with a gross of 1050. I fly with my son fairly often, and together we weigh about 425. Nice you and your passenger are light enough to make it work for you. My son and I should lose about 50 pounds between us.

[rogerh12]

I hear the EA-81 is popular with the Avid crowd, and they seem to like it's power/climb well enough, so would it not work on a Kitfox-3 or 4 just as well?

I think I saw a typcial install weight of about 205 lbs on a previous post, kinda on high side alright, but you might get up to 85HP out of it (at the prop).

Roger

[SkyDave]

What???? my kitfox 3 with E81 mod was special built cowl...as to CG its 11.26 with 10.2 max forward and 14.28 max aft at 1050 # with 2 people 178# each plus 7 gallons fuel......flight time 250 hours on aircraft now...have no problem take-off or landing within 250 ft...1992 Rotax was unreliable hence the E81 :)

[rogerh12]

Howdy all;

If asked, I guess I would say a 205 lbs EA-81 Subaru install is too heavy for a Kitfox-3, but then again someone else might say my 180 lbs VW engine install is too heavy for my model 4, then others have said the 165 lbs Rotax 912 install is too heavy. I guess every engine is too heavy for someone out there !!!


Regarding performance and reliability, the Rotax 912S is best for the Models 3 & 4, I think most everyone would agree to that, but I personally don’t have the $20K+ it will take to put a new one in, or the $10K it will take to rebuild it later, but I do have the $3K it will take to get a used VW and the $1K it will take to rebuild it and I think a good used EA-81 can be had for about the same money.


For me, when it comes to putting an engine in my plane, it’s “low-dough” or “no-fly”, it’s just that simple, and I don’t think I am the only one in that situation.

Roger

[SkyDave]

Thank you Roger Thats another big reason I fly what I fly.....your so right

[HighWing]

I know the guy C5 is referring to. We became friends because I worked in the city where he lived and except for the engine, We were building the same airplane. As I understand, He chose the EA-81 because NSI never published service bulletins and the frequent ones from Rotax bothered him a bit. He was retired airline and could have afforded any engine. His plans were to fly it out of his home strip which was on a vineyard. Actually at the time we both started, the factory was supporting the NSI EA-81. Then for some reason they stopped the factory support. The airplane's performance disappointed him some as the hours would indicate.

I am always intrigued by the cost of overhaul being entered into the discussion. I bought my present project 80 horse Rotax used with 150 hours for $9000. With my first airplane, over nine years I flew 900 hours or approximately two hours a week. For me, at that pace it would take 20 years to consume the TBO hours. In that time, I'll need a new roof, and maybe a casket or two. If you are like Ray Volk and put a thousand hours a year on your airplane, I can see the concern. I know a few who put a couple of $$ in a "can" after each flight for the future. I do understand budgets though. Being retired, the cash flow is not the same as it once was and my present project will likely price out at almost the same my 19 year old project did. It can be done.
Lowell

[SkyDave]

Plus with dual exhaust with mufflers the E81 is so quite plane is stealth and headset not needed except for radio calls

[Marshawk]

Hi Skydave , I have bought a avid + project and it came with Ea81 and I am working on getting it install. It's great to hear some positive info on the soob.I cannot afford a 912 right now so its full steam ahead on hanging the soob on.I just got my TBI-40 carb today for it and almost have the cowling fitted on.

[SkyDave]

not familar with TBI-40 carb used a ford bronco carb on my E81

[rogerh12]

I am still hoping to buy a Kiftox VW firewall forward setup off a guy with a flying VW powered Kitfox. His 3 Avid buddies fly the EA-81 and like it so much that he is willing to swap engines out and join the EA-81 club. Plus, they gave him an EA-81 engine for free!!!

For me, it’s kina like “better the devil you know” as I have had several VW engines and know the strengths and weakness best, and what to look for in general. Plus, Great Plains VW is less than 4 hours from my house, so I can pull the engine and drop it off if needed.

If I can get the VW setup, I plan to change the engine from 2180cc to 2273cc, and drop the compression to 7.5:1 so I can run 87 octane car gas. Also, install aluminum cylinders to save an extra 10 lbs off the engine weight (it also helps cool the engine), which will give an install engine weight of about 170 lbs with about 75 HP peak for takeoff, and burn about 4.5 gph at cruise.

Roger

[rogerh12]

Hi Dave;

Great video of the two kitfox, nothing like a side by side comparison.

I think the VW direct drive (the 2180 cc) setup produces about 25% less static trust at take off, as compared to a 582 (as I recall). So the take off role of the VW craft would require about 25% more time to reach lift off speed (using F=MA). So if the 582 can take off in 4 seconds and covered 264 feet (for example), I would expect the VW kitfox to require a take off role of 412 feet (if I got my math right).

Of course, this assumes the 582 can maintain the same 25% greater static trust level over the VW prop, which it probably can't as one property of a flat pitched prop is that the static trust drops off quicker than a more pitched prop as forward speed builds, so these numbers are or more like worst case for the VW.

Below are the actual performance specs from a flying VW powered Kitfox-4 that was up for sale last year (The 32" pitch on it would be consider pretty flat for a VW (my Sonerai had a 46" pitch on it))

Hope this helps
Roger

Specifications N53RJ KitFox IV Speedster

powerplant
propeller
length
height
wing span
wing area
seats
empty weight
useful load
gross weight
fuel capacity
range
Great Plains VW Direct Drive 2180cc 76hp
Ed Sterbra Wood 62x32
17.8ft
5.8in
28.8ft
116.8sq.ft
2
700lbs
500lbs
1200lbs
27gal
570nm
Performance
takeoff distance, ground roll
rate of climb
max speed Vne
cruise speed @ 7500 msl
fuel consumption @ cruise
landing distance, ground roll
service ceiling
300ft
1000fpm Single Pilot, 700fpm Dual
140mph IAS
110mph TAS
4.5gal/hr
300ft
11500 ft
Limitations
design manoeuvring speed (Va)
never exceed speed (Vne)
stall, power off (Vsl)
landing approach speed
106mph IAS
140mph IAS
37mph IAS
60mph IAS