Author Topic: More foam fun (Read 6244 times)

john vlna · « **on:** February 06, 2014, 07:14:22 PM »

I went into the Dollar store the other day and they had some nice black foam board. I just had to use it and build something. This is a real old design. published in FM back in the 50's. FM back in those days stuck little half page model ideas in the back pages. I doubt anyone ever built most of the ones published. One was called the Delta Fighter, intended for 1/2A. It showed an OK Cub as I recall. I actually built one back in the 50's. No stunter, just went round and round.

For foam I enlarged the plans and intend to use electric power. Also a KFm2 type wing is used for more lift than a flat plate, we'll see.

By the way the TBF in the background is for 1/2A carrier, more details on that board.

john e. holliday · « **Reply #1 on:** February 07, 2014, 09:34:07 AM »

Isn't that most of us did back in the day. Build it and fly it round and round until it was replaced with another design. Read about stunt and combat but had never seen one do it. Then at Wyandotte County Park someone was flying a big plane, at least to me it was a big plane flying all over the circle. That is when my American Boys started getting a work out. What did I know back then. Dad did see me do my first loop with the American Boy.

john vlna · « **Reply #2 on:** February 07, 2014, 11:17:20 AM »

The American Boy was my first plane, early 50's. The first flight I didn't know to try and keep the lines tight, but eventually we got in the air. Spitzy .045 powered.

GGeezer · « **Reply #3 on:** February 10, 2014, 05:13:04 PM »

Wow John, I thought I was the only one that had ever built the Fix-it Wright's FM Delta Fighter! This was my first successful C/L airplane and was powered by my first 1/2A engine, the OK Cub .049A. I was a young kid in the early 50s living out in the country so I didn't have anyone to help or advise me. There was no balance point shown on the sketch so the plane turned out to be very nose heavy, made worse by the tank mounted engine.
My mom would hand launch for me and if I held full up elevator, the model would just fly level if I had a good engine run. Of course, as soon as the engine stopped, the model nose dived into the ground breaking the wooden prop... but it was wonderful!
Your post really brought back the memories of the bright red model. I'd like to build this model again and see how it would fly when balanced properly.

orv.

john vlna · « **Reply #4 on:** February 10, 2014, 07:53:44 PM »

Orv
Small world. As I recall mine was nose heavy too, but I used the OK Cub that needed a tank so maybe it wasn't quite as nose heavy. I didn't know a lot about balance back then either.

john

George · « **Reply #5 on:** February 12, 2014, 07:16:37 AM »

Quote from: GGeezer on February 10, 2014, 05:13:04 PM

Wow John, I thought I was the only one that had ever built the Fix-it Wright's FM Delta Fighter!
orv.

Never built the Delta Fighter but I always enjoyed Fix-it Wright.

Remember the mud-walkers they used for muddy fields?

George

GGeezer · « **Reply #6 on:** February 13, 2014, 02:25:40 PM »

George,

The only magazine I could get from the drugstore in town in the early 50s was Flying Models. I didn't have any model airplane mentors to learn from so I found the Fix-it Write cartoon in the magazine not only entertaining but also very educational as far as modeling was concerned. It also dealt with relationships... I could however never get my sister to be like Bunny!
This cartoon had a good and big impact on my early life.
I do remember the mud-walkers.

Orv.

George · « **Reply #7 on:** February 13, 2014, 08:28:54 PM »

Everybody had a crush on Bunny! ;-)

George

Dan McEntee · « **Reply #8 on:** March 12, 2016, 10:07:15 PM »

What issue was this model in? I don't remember it and would like to look it up.
Thanks a lot,
Dan McEntee

john vlna · « **Reply #9 on:** March 13, 2016, 03:09:21 AM »

Dan
I'll have to look it up, my filling system ain't good. It was not one of the major articles. Remember how they put little 1/2 page stuff towards the back? Well the delta fighter was one of those.
John

Dan McEntee · « **Reply #10 on:** March 13, 2016, 08:27:24 AM »

Quote from: john vlna on March 13, 2016, 03:09:21 AM

Dan
I'll have to look it up, my filling system ain't good. It was not one of the major articles. Remember how they put little 1/2 page stuff towards the back? Well the delta fighter was one of those.
John

Yeah, I'm familiar with those. Usually a small glider or something, but pretty neat. I would just go down to the basement and start looking, but then I get side tracked by finding other stuff and then the whole day/evening is gone! Let em know if you think of it.
Thanks a lot,
Dan McEntee

GGeezer · « **Reply #11 on:** March 13, 2016, 01:05:39 PM »

The plans take up about 1/2 of page 30 in the Feb. 1956 issue of Flying Models.
This was my first flying control line model and I'm building it again to see what it was really like.

Orv.

john vlna · « **Reply #12 on:** March 13, 2016, 06:54:06 PM »

Yep, that is it Orv. I went back a re-read your comments. You were probably very nose heavy back in the 50's. The plan as drawn would tend to make it nose heavy. The real CG should be at least 4" back from the nose. I started flying in 1950 and by 56 I had a lot of experience. I also flew FF so I was very aware of CG location.
John

john e. holliday · « **Reply #13 on:** March 15, 2016, 10:06:44 AM »

Orv, thanks for the plans. Just printed off the page and it looks like a fun plane for the grandkids over grass.

john vlna · « **Reply #14 on:** March 15, 2016, 08:46:54 PM »

Doc
If you make one scale it up a bit. I think my foam version is 125%. I am getting ready for bed so I will go out to the shop and measure it tomorrow .
John

john vlna · « **Reply #15 on:** March 16, 2016, 10:28:47 AM »

Doc
My foam version is bigger than I thought, 158% bigger than the original
John

GGeezer · « **Reply #16 on:** March 17, 2016, 11:15:07 PM »

Hi Folks,

It is quite possible that the magazine needed some more content and artist Gill Evans cooked up this design in haste. I suspect that it was never built and tested. Almost any engine you put on the model will make it very nose heavy as was the case with the one I built as a kid. Keeping this model in the air required full up elevator and it just mushed around not gaining any altitude.

John's estimate of the CG needing to be about 4" behind the firewall is probably pretty close from the internet research I did. If you balanced the model at the point as shown on the plans, the bellcrank pivot would be on or ahead of the CG... not good for keeping the model at the end of the lines.

I will move the pivot farther back to 4-5/8 to 4-3/4" from the firewall. The model will need some tail-weight and may end up too heavy for the wing area but I'm going to give it a shot. My object is to prove the weakness in the design... or how a kid can get duped!

John's enlarged design may be a better approach. The wing now is only about 45 sq. in., quite on the low side. 65 or 75 would be better.

Orv.

Orv.

Serge_Krauss · « **Reply #17 on:** March 18, 2016, 12:17:26 AM »

Don't forget: it's the lead-out exit position that counts. Just put the bellcrank wherever it fits and located so that you have minimum lead-out bend at the tips.

SK

john vlna · « **Reply #18 on:** February 09, 2018, 11:57:18 AM »

Well I have been away from this project for a while. It got put on a back burner. By the way the model is about 50% bigger than the original published in FM. I put a KFm airfoil on it. That is what the step is about on the top

I got back to it this week. I calculated a CG at about 7" from the firewall. To check I test glided it like a hand launched glider. It seemed right. I wanted to be sure so I rigged a fishing pole and 10 feet of line and whip flew it. Seems to be just right. OK flying level and slight climb/dive. To much up and it is quick to stall. My plan is to have it takeoff vertically. But I haven't tried that yet, nor have I tried powered flight. Maybe this weekend if the rain holds off. Some pics attached

john vlna · « **Reply #19 on:** February 10, 2018, 10:41:35 AM »

Got out ahead of the rain today. The first flight , as they say, flew off the board. Perfect vertical takeoff. Nice and stable in level flight, Not a stunter but will do a respectable overhead and I think could go inverted. 100 times better than the 1950's original. If you get into the wind just right it is possible to land vertically, but on grass it keeps falling over.
Power system is a Turnigy 2730-1500, 12a esc, 500mah 3 cell and 2.4GHz throttle.