Mark Jenks Sport 400 - August '99 construction article - RC Groups
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Sep 28, 2001, 01:52 AM
Still learning.....
JWC's Avatar

Mark Jenks Sport 400 - August '99 construction article

I just finished building and flying Mark Jenks Sport 400 from the E-Zone construction page, dated 01-Aug-1999. I'd love to foam at the mouth and rave about this thing, but I'd like to ensure that Mark gets his well deserved atta-boy. I didn't see any e-mail address for him, but is there anybody who can forward my comments to Mark for me?

I've built about a half-dozen electrics from kits and several "good idea, poor execution" planes of my own design, (two even flew) but this is undoubtedly the best electric plane I have flown. It also happens to be my second balsa plane and first plan built plane, (but not my last.) Although I enjoyed the construction immensely, I was very nervous about the test flight. I don't even have the words to explain how thrilled I was to fly that plane. You know that 'Christmas Morning' feeling in your stomach when your plane screams out of a dive at 50 MPH? I still got it. Fast, maneuverable, yet very stable. No 'twitchy' characteristics, great inverted, inside and outside loops from level flight, will loop over and over from level flight. Put it in a bank and it just keeps going round until boredom sets in. (It never did.) Here's something I didn't expect though. When you chop the throttle and line up for a landing, that plane just floats on by. Isn't it supposed to lose altitude? Good thing I saved some juice for a go around!

Mark, great job, great plane. Thank you, more than I can say.

Here's the specs on the Sport 400:

Span: 36" (okay, I had to change something-I made a built-up wing)
Length: 24"
Weight: 16oz
Power: Speed 400 6v, 8 cell 500AR, Gunther prop (first flight = cheap prop)
Radio: Hitec Focus 3 AM receiver w/o case, Graupner ESC, 2-HS 85mg servos

Jeff Charlot
Kodiak Alaska
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Sep 07, 2003, 04:08 AM
Registered User
Sluf7's Avatar
Hey have you still got the plan for the Sport 400 if so could ya if not to much troubleflick it my way. It seems the link on the Article has timed out and can't find reference to the plan.

Here's a link to the site where some friends up sized the plan to what they call the Sport 600.

Cheers Sluf7
Sep 07, 2003, 05:25 AM
Ah nuts, almost made it
pgjoh1's Avatar
I built one of these a while ago but it didn't fly very well because I stuffed up the wing when building it. (I'm not a very good builder). One day I might build another wing and give it another shot. As you can see, I made a few mods.

Sep 16, 2003, 06:50 PM
Scott Zastoupil
szastoupil's Avatar
The Sport 400 plans can be downloaded here:
Sep 16, 2003, 09:45 PM
Registered User
I've built three of these. #1 bit the dust from radio problem. #2 flying with 6 v sp 400 2 years after construction. #3 has mega 16/15/4, and only foam wing, others are built-up. I for one don't think the author got attention due, the plane is simple to build and performs great! Right up there with M Rittinger's P-51 ( of which I have also built three )
Dec 13, 2005, 01:10 AM
AKA BillyKillaWatt
Billy Haynes's Avatar

My Sport 400

Russell2, we seem to have some things in common The Python is one of my favorite planes. I'm on my third one also, but I cheated a little on the last one. It was the lazer cut kit from flying hobbies (I think that was who it was from anyhow). My Sport 400 is built, but not covered yet. This is a very quick building plane. I started on mine @ 11:00pm Sunday night and the airframe is finished Tuesday @ 12:00am. Just over one day! Granted I only got three hours sleep during this time My guess is 12-14 hr of build time. Now to figure out a color scheme......
The gear I plan to use= 16/15/4, PHX25, Prop? (TBD), Electron RX, (3)HS-55, 3s 1320. I think it'll move on with this set up I'm going to use two aileron servos, so I can use some flaperon to make handlaunching and landing easier....... I hope.
Last edited by Billy Haynes; Dec 13, 2005 at 01:20 AM.
Dec 16, 2005, 01:48 AM
AKA BillyKillaWatt
Billy Haynes's Avatar

Covering is done!

The airframe is finished. I think the colors I chose will show up good in the air and provide a nice contrast between the two. Airframe weight is almost 9oz's. I made my own control horns. The ele horn is carbon fiber angle that is epoxied on and one screw is ran through it to a carbon backplate that is also epoxied on. The aileron cont horns are just flat carbon epoxied into the aileron. I hope to get the gear installed by Sat. morn so I can get a test flight (or two ) in before another band of bad weather gets here.
Dec 16, 2005, 01:56 AM
AKA BillyKillaWatt
Billy Haynes's Avatar
I forgot.. I also made a louver for the air exit (as seen in one pic). The plan is to reduce drag and still allow airflow out of the fuse.
Dec 16, 2005, 10:36 AM
Scott Zastoupil
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Very nice covering job! I'm guessing you used the light box for cutting out the unique flame covering pattern.

Dec 16, 2005, 11:48 AM
AKA BillyKillaWatt
Billy Haynes's Avatar
Scott, yes... kinda. That table is my covering/plans table. I just turn the lights on when I tape printer sheets together to make a full size plan. The glass surface makes it easier to cut monokote, espically for things such as the flames.
Dec 17, 2005, 08:30 PM
AKA BillyKillaWatt
Billy Haynes's Avatar
I finished putting the gear in last night. I used a ProSpin 29mm prop adpt./spinner ( Spinners ). When I went to balance it, I couldn't find a CG marked on the plan!?! Does any of yours have the CG marked? I didn't find anything on the CG in the construction article either. I figured a CG range of 25-30%MAC would work for a few test flights. With the gear in and the 3s 1320 all the way up front it balanced at 30%MAC (1.8" from leading edge). I was able to put two flights on it today. The first was with a 5.5X4.5apc. The hand launch was a nonevent with the flaperons on. It took several clicks of left aileron and one click up elevator to get it trimmed out. The second flight was with a 5X5apc. I could tell it was a touch faster than the 4.5, but not by much. It's not as fast as I thought it would be, but pretty close. I got several positive comments from some of the guy's at the field on how fast it was. I think I'll like this little plane From the building board to the air in less than one week....... I think this was the quickest building plane I've done to date, not counting the foamies of course
Dec 17, 2005, 08:32 PM
AKA BillyKillaWatt
Billy Haynes's Avatar
O yeah. The ready to fly weight came in just under 19oz's.
Dec 17, 2005, 09:00 PM
AKA BillyKillaWatt
Billy Haynes's Avatar
OK....... I'm just blind! I've started cleaning up my building area. As I went to roll the plans up to put it away, I looked it over one more time. What ya know...... The CG is there after all! It's on the fuse side view. I was looking all over the plan for the CG marked on the wing/airfoil drawings. I just over looked it marked on the fuse

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