jet22b

Kostas1;
Here are the ones I shot today in the rain!!!
Sonny
aka
jet22b

eddieC

My Feedback: (2)

I'm lurking on this thread.

How's the cooling air for the rear engine? The full-scale had issues at first, Cessna fixed it soon after it came out.

It is a 337 - just with a gear problem, so it's flown with gear extended! 

Good luck with the maidens.

rcflunky

Sonny, your plane looks great, hopefully you get to maiden it soon. It looks like many other's are building this plane now. Herc I can't wait to see pics of yours completed that thing looks awesome, and it should win an award or Seagull should give you another one and keep that one on static display. Welcome to the rest of you 337 builders this plane is a pain to build but fun to fly. I hoped to start a new build soon on one of these, it should go a lot faster than the first one. Happy building.

Joe
aka
rcflunky

Herc Pilot

My Feedback: (15)

Don,

No, We didn't have issues with the rear cowl width, it fit pretty well that way. If you push it further up on the fuse will it help or is there still too much gap? You could always add a little balsa sheet to the top of the fuse around the scoop area until it's just right and just recover that small section. White ultracote is a dead on match. Still a lot of work for an 'ARF".


eddieC

Welcome to the thread. Joe (rcflunky) is the only one to have flown this plane from the thread to this point but had no issues with rear engine cooling. Sonny (jet22b) has run his engines and completed taxi testing. From what I'm gathering, the rear engine runs about 50 degrees warmer than the front, but as long it's kept in motion so the scoop forces air over it and it's not run too long on the ground, I don't think there will be many problems. Most everyone has opened up the scoop on top. We are running Spektrum's temp telemetry on ours so I'll report that data back here when we get test and flights in.


Adam aka Herc

Free Bird

Here's the trim scheme that I'm thinking of doing, along with refitting the cowls. I think this model has a lot of potential.

FB

donddsms

My Feedback: (1)

Deleted.

donddsms

My Feedback: (1)

Hi guys. Photos didn't upload so I'm trying again.
I completed my dissection of the rear cowl and it's back together. There is some improvement in appearance, and it was easier to accomplish than I expected. The saw lines actually look like panel lines, maybe I'll add some rivets to make it look more psuedo scale like. Or else I will cut a strip of covering and just cover it up. I still have a little trimming and finishing to do, but I'm glad I made the change. And I finally figured out how to get the pictures posted!
Don

donddsms

My Feedback: (1)

This is how I joined the wing tube to the center section so that it would be removable. I plan on leaving the tubes on the wings between flights, so the main body takes up less width during transportation to the flying field.
I used 3/8 wood dowel, cut and center drilled it to receive a 4-40 hex head bolt. This was placed up against the outer plywood rib, just over the wing tube, and epoxied into place. After mounting the tube in the wing, I inserted the remaining tube into the center section and measured where I needed to make my hole for the 4-40 bolt. In that area I epoxied about one inch of dowel into the wing tube, to give me something to anchor the 4-40 bolt.
The result will make it easy to transport and quick to assemble the plane at the field. I've used this on other planes successfully.
Don

jet22b

Don;
The back cowling looks great and I like the way you did on the wings!!! Later today I am going to ground run the engines for 5 mins and get a head temp on the engine right after shut-down. I will post my finding on the temps right here. Now I am using two Evo .46 engines and the back engine is set 3 click on the rich side.
Don keep the up-dates coming and I hope to maiden my 337 if the weatherman got it right. Right now he is calling for blue skies and a temp of 60 degs!!!
We will see!!!
Sonny
aka
jet22b

donddsms

My Feedback: (1)

Thanks Sonny,

Here's what is hanging out of the center section hole. Reminds me of that robot from "Alien". I decided not to cut into the sheeting wood, and to leave the hole the way it is. I was worried about weakening that area. I plan on taping the receiver to that surface, and there will be wires dangling into the hole in the cockpit deck. I might wrap them all in a tube made of grey construction paper. I treated the lights as if they were another channel, so there are a few "y" servo extension wires inside too.
Don

donddsms

My Feedback: (1)

The Tru-Turn spinners where here when I got home from work. Still need to do a few tweaks and get the struts screwed on but I am getting a bit excited for spring to get here. AND Daylight Savings Time!!!

Don

jet22b

Hi Guys,
Here are the numbers for the 5 mins run on the back engine with the cowl in place. The weather was clear, no rain and the outside temp was 57 deg. Now for that 5 min ground run, the throttle was moving like it was in the air. When the time was up, I use my Duratrax Flash Point Infrared Temp Gaga to get the head temp and it was 151.5 deg fahrentheit. I was using Cool Power 15% heli-mix fuel with a OS #3 glow plug. Now the front engine came in at 115.2 deg F, same set up as the back engine. So you see the back engine do heat up, but I am hoping that the temp do not go very high over my bench mark of 151.5 deg. One thing I can say, with out the wings in place, the front engine do push a lot of air back, but its hard to tell how much of that air go inside the back cowling. The props I am using are the APC 11x7 props. I hope the weather man is right for this weekend so I can maiden this bird!!!
Please stay tune!!!
Sonny
aka
jet22b

jet22b

Don;
She is looking good!!! Please let me know how she fly on the 3 blade props. I was thinking of going that route and I do have some 11x7 Master Screw props in the prop parts box!!! It look so good with the 3 blades on her!!!
Sonny
aka
jet22b

donddsms

My Feedback: (1)

Thanks Sonny, and thanks for the temp info on the engines. Those are Master Screw 11/7 props. I still need to balance them.

I need to go back thru this thread but there are comments that resonate with me about the back cowling. Adam made scale cut-outs that must help a great deal with air flow, and you mentioned widening the scoops on the center section. Also, someone asked why we are not opening up the area around the rear spinner, because the scale plane has a gap between the cowl and the spinner. I'm sure that would improve cooling.

Another thing I have been thinking about is the wheel wells for the retracts. Although we don't use retracts, there is the option of cutting out wheel size holes for the wheel wells and pretending we have retracts, and it would look scale. Those retract holes would allow for tons of air flow. I'm not ready to cut those circles out but I will do it if I have heating trouble back there.

Don

eddieC

My Feedback: (2)

Once in flight, the cooling situation will be known. Hopefully it's a non-issue. Nitro engines do run cooler than their gasser counterparts. Nitro engines cool quickly on shutdown, so get the IR temp as soon as you taxi in. Gassers tend to have more heat rise on shutdown. 

jet22b

Don,
I think we all look at the opening on the air scoops on the center section and we want to get as much air as we could going over the rear engine. As far as retract gear for this bird, no one make them and if you look at the full scale setup, you ask yourself, what was Cessna thinking!! It would look good in the air with the gear up. Now the wheel well cut out for the retract is on my list and we be done if I have a cooling problem in the back. This is why I am waiting for a good day so I can maiden her to get answer to a lot of question that have been posted here.
Sonny
aka
jet22b

neilh2

I am considering buying a seagull 337. I have a pair of E Flite 32's I plan to use. I have concern about placment of the battery and balancing the model. I would appreciate any help you can offer

jet22b

Hi neilh2,
Welcome to the 337 build thread!! There are some guys you are going e-power on this bird and I hope that will help you out. I know the next C-337 I will build, will be e-power. So I am too looking forward to all the e-power post.
Again, welcome to the thread!!!
Sonny
aka
jet22b

eddieC

My Feedback: (2)

flycatch

My Feedback: (26)

The USAF used the 336 for a FAC observation post.

Herc Pilot

My Feedback: (15)

Free Bird,

I like that color scheme, real classy! That should be fairly easy to accomplish without removing a lot of covering. I think you'll be happy with the personal touches.


Don,

Your Skymaster is looking great. I like what you did with the wing tubes and you did a nice job on the cowls. The spinners look good as well. We were debating on what size props to turn if we flew with 3 blades. Have you run your engines with them yet? Also, your comments about the cooling is along the exact same lines we were thinking. Our last resort will be to cut out the wheel wels if there is still a cooling issue, but like you, we are hoping to not have to go that route.


Neilh2 and flycatch,

Welcome to the thread!



Adam aka Herc

donddsms

My Feedback: (1)

Had a strange set back last night. I powered up the model and the transmitter, and the rudders locked hard to the right. The other control surfaces were fine, and the nose gear turned fine. I turned everything off and tried again, same thing. After disassembling the servo leads from the receiver, I found all channels worked, but the servos on both rudders were burned out. They were brand new Hitec HS-225 MG servos from Tower. I am using a Spektrum DX8 transmitter, a Spektrum AR7010 receiver, and Hydrimax ultra 6.0V 2000mAh NiMH battery, all new since November, and yet to fly a plane. I am new to 2.4 GHz, for the past 10 years I've been using a JR XP8103, so maybe there is a learning curve for me. I talked to the Horizon rep, the Tower Hobbies Rep, and the Hitec Rep. My radio and receiver are going back to be checked out, and the servos are going to Hitec to be checked out. So I won't be flying anything for awhile. No one had a clue about how things failed. Has anyone had this happen? How fortunate that it happened in my living room and not while flying. The reps also warned there is the possibility we may never know why. You can imagine how anxious I will be the next time I use this equipment.
Don

eddieC

My Feedback: (2)

We've not had servos burn out, but more than once have had radios that have lost their 'bind', with Spektrum and Futaba 2.4 systems. These are on aircraft that have been flown several times, not new installs on the first few flights. Have also had just one channel lock out on a first flight of day, rebinding fixed it. These were all during preflight. 

Kostas1

OMG that is awesome.

I wish I had the money to buy one for me too!

donddsms

My Feedback: (1)

These are the last parts left in the box. I'm not sure if I am going use the white fairings, I can't decide if they improve the appearance or not. What do the rest of you think? Also, the three red fairings don't appear in the manual so I guess I have creative license to place them anywhere I want. They look like they could cover the exit ports for the rudder and elevator push rods, or maybe they are scoops to improve air flow to an engine. Or very tiny wheel pants. Has anyone found a use for these?
Don