reaaz

Have decided to document the build of this Kit I obtained, F20 Tigershark ( Cressline ducted fan kit) as I think it would be a nice challenge to get one of these older Jet kits flying.Also would love to build something this winter season.
So your welcomed to check out this build, I'm expecting it to be flying for next summer.
Not much of these kits flying if any, but who knows

Specs of the Plane are Length 70"+, Wingspan 48", Weight 10-12Lbs, Power: Dynamax 90 sized ducted fan units
Fuse, fiberglass, Wings & tail: foam

reaaz

The fiberglass fuse came with the Canopy molded in, so this can just be painted in or you can cut & install the included Clear canopy.
I decided to install the clear canopy, thus it was cut & trimed to fit. Later on I will be framing the canopy openign & making the Canopy removable for Ducted fan wand starting & nose equipment installation

reaaz

Next step was to figure out the ducting... The Kit comes with molded ducts to the fan. They weren't to much to my liking, but I decided to use them anyway rather than making new from scratch.

To make the ducting work as efficiently as they are able too.. I made a ply ring, sized exactly to allow the lip of the duct to slide inside the Lip of the Dynamax housing.
The Clamshells were then epoxied to the ring

ron Sweeney

Hi Reaaz, you have at least one interested guy. I have the cressline F5. It has been hanging around my workshop for 20 years. I will be interested in this build and your choice of adhesive. I am not a fan of polyester and have never ever found a really good bonder and I think I have tried them all. Ron.

cetigershark

Ron,

have you ever tried Pattex Stabilit Express? I am just building an A-4 Skyhawk from Yellowaircraft with a Wren 44. They recommend Stabilit Express to bond the Polyester..
And i think it works great.

Christof

Ram-bro

My Feedback: (101)

Heck, I will be watching. Its nice to see that D/F is still alive and kicking and also this is one of my favorite jets. I wish I could find an F-5/ T-38 kit.....not an arf but a kit

madmodelman

Ron, Christof is spot with the Stabilit Express.

I used to a lot of boat building and this stuff is fantastic for gluing plastics etc. You must try it.

proline8000

My Feedback: (12)

Guys I have been using West system six10 epoxy to bond to polyester with great results.

proline8000

My Feedback: (12)

I have also used Plexis MA but it is hard to find and a little pricy. http://www.jamestowndistributors.com has it. Here is le web address for the Structural Adhesive http://www.itwplexus.com/products/selector.cfm

k12rc

have you tried E6000 wallmart has it it want let go

ron Sweeney

Hi Christof, yes I have tried Stablitt express. It always appears to be a good bond but it will not withstand shock loads. I have an early yellow Aircraft F18 and this was a really difficult airframe to bond anything to even after serious scuffing and de-greasing. In the end I used polyester resin. I tried several adhesives on a test piece cut from the canopy mold.
I actually started my F5 a few years ago and installed the Fan mounts to the fuselage sides and changed my mind and decided to fit a turbine. Although the mounts covered a big area they came off quite easily and cleanly with a bread knife behind them. Maybe I am asking too much of the glues, But I don't want to obstruct this thread. Ron.

cetigershark

Hi Ron
I used now a whole package of Stabilit on my Yellow A-4, I hope it holds. I sanded and then degreased the bonding area.. and I made a nice (don't know the english expression...) smear with a finger around the formers. So far it holds.
Stabilit cures pretty fast, the polyester resin I have smells like hell and takes overnight to cure...

I wonder why Yellow Aircraft and other manufacturers cannot switch over to epoxy fuses...

Regards,

Christof

ron Sweeney

Hi Christof, as far as I know they have changed to epoxy which is more expensive and a less healthy option unless somebody knows better. It is lighter but more brittle in my experience but quicker to cure and mass produce.
I currently fly a Peter Nye cougar. Pete has been molding models for over 35 years and he would never use epoxy, much to my frustration. Ron.

grbaker

My Feedback: (29)

Years ago I used silicone based automotive adhesives with good results (like Permatex RTV)

reaaz

Hi Guys, Ron, Ram-bro, Pro, K12, Mad etc..
Glad to see youall here.. these are definitely not the modernday "snaptite" arf kits (if jets can ever be that simple) so hope we can all learn a few things & hope I can ask advice from everyone here. That concerns youall have with polyester & epoxies... yes, very necessary to know. What do you all think about hysol?

Today I test fitted the spar & Unsheeted wing blankswings.. to see how it goes
Note that spar has been cut to lighten it on outer portions & the center section of spar is form cut to fit over ducting. Strenth will be regained here by sandwiching with 3/8 X 1/2" birch landing gear rail stock later.

Pics also show engine & fan unit I have planned for this machine & how it snuggly fits exactly over ducting. I ended up making 2 ply "duct" rings before i got the fit I wanted. Think it will pay off, with flight efficiency.

I also Installed conformal ducting "balsa sheets" to correct the flow inside the duct & cut away the center section to save weight. This will be glassed later on

k12rc

I bave one built but not painted also have the plans for it if you need anything pictures ill be happy. To take some. I USED E6000 to hold formers in used it for 20it yrs now never had one come loose I think iam going to use a super bee in mine

reaaz

One of the thing I wanted to figure out is if anyone has mounted these engines Inverted. any issues with running etc..
It would have the advantage of easier glow plug acess & easier rear ducting installation.
Otherwise I don't plan on making the traditional top hatch as I see it as being unnecessary (now that we have prob starter through the inlet or Canopy opening ) & it will also weaken the structure, not to mension add a little more weight to airframe.
Engine removal/installation will be through the belly hatch & nothing else.

reaaz

K12, thanks for the offer.. Your welcomed to post as many pics of your Cressline F20 as you wish. There is a lack of build/finished pic documentation on this plane... so bring it on Thanks

I will definitely go look for the E6000 before I glue on the engine bearers.

Glad your planning to go turbine with your one. If you do the install this winter, add pics too. (I'm planning to build mine to be able to handle a turbine later on as well)

k12rc

I never had any problems running eng inverted just prime fuel line before starting just be careful not to flood

hooker53

My Feedback: (106)

Nice build thread. I need to find me one of these. Have a nice Wren 44 that would do well with this jet.

k12rc

here are a couple going out of town to airshow will post any pic you need just let me know what you need E 6000 is in the craft section at wall mart or Michael or hobby lobby craft stores

mongo

My Feedback: (15)

hey 12, that appears to be the F-5, rather than the F-20. dual exhaust instead of single.

reaaz

Okay, thats it, decision made.. this engine is going in Inverted!
Nice Pics of your F5 version by the way.. Take it down, dust it off & strap in that Super bee

k12rc

youre right its been so long sense ivehad it down i forgot

Ram-bro

My Feedback: (101)

this is the setup I had in the Byron f15 twin, had to invert plane to start and it makes it easier to service the engine, plugs, carb etc. If you dont invert consider using onboard glow