CorsairJock

My Feedback: (90)

The stock wheels are 3 1/4", so going with them would not be a problem, AND it will require less work.

85 or 90: that is the question. The stock retracts seem to be slightly less than 90, but I don't think they are 85 either. I'm thinking the 90 will be a little more forgiving, in that it will have a slightly outward canted stance. It's really a question of how much dihedral is in the wings, and I don't have the answer to that either. There appears to be less than 5 deg (each wing), which means that using 85 degree retracts will have the strut canted INWARD slightly. It's a tough call, you really couldn't go wrong either way. Anybody else have an opion on that?

BTW: only had time for 1 flight tonite, but it was beautiful.

Kempdawg89

Thanks Old Bird - I wasn't sure I was right because it seemed so obvious that I didn't understand why Top Flight did not incorporate this into the design.

I am planning to use the stock retracts until I invariably destroy them, and I like the idea of adding some fiberglass. I also think some blind nuts and maybe longer bolts that extend into the wood we add below the mounts also makes sense.

Keep me posted on how your mods turn out - as for me I am going down to the shop to glue the wings together. I am not looking forward to this, one of my most hated ARF construction tasks, because it is so stressfull! The tape method just seems like the wrong way to do this, its not very strong, allows for sideways movement and pulls the darn covering up ARGHHH. I think I am going to try using rubber bands around those plastic pins and a clamp in the retract servo area as well as puting the wing bolts in halfway and rubber banding them from both sides as well. Does this make sense to anyone? Anyone have any tips on this process?

old bird

kempdawg, Here is my method for gluing wing halves together. Get two short pieces of dowel, 3' or 4" and stick these through the holes for the wing bolts. No dowels? use wooden pencils. Hold the trailing edge together with rubber bands over the pencils, top and bottom. Hold the leading edge together with rubber bands over the locating dowels. When you have this clamping sequence figured out, take it apart and mix and apply your epoxy, then clamp the wing again with the rubber bands. Be ready with some alcohol and paper towels to clean up the oozing epoxy, it will keep coming out for several minutes. If you think that you are going to have troubles with the wing halves slipping on the slippery epoxy, sprinkle a few grains of fine sand on one of the wing root ribs after you apply the epoxy. This will key the two halves together until the epoxy sets.

I just finished adding some birch plywood reinforcing under the gear mounting rails in the Mustang. I'll be using longer screw that reach into the new wood for some real grip. The new wood also fills the gap between the rails front and rear and the body of the Robart retract.
The stock retracts appear to be a cheap copy of the Robart 608 design. Leave it to the ARF makers to copy a good product with crappy, cheaper material.

Hope this reaches you in time for the wing joining.

Best regards from old bird.

michaelbbbb

I'm running a APC 16x8 Prop on the Saito 125 and getting about 8800 RPM. Someone also had asked about prop clearance. That is absolutely no problem with this size.
This bird sits nice and high, so 16" doesn't even come close to being an issue.

michaelbbbb

I went with the 608HD at 90 degrees, and mine fit/look good. They are straight down from wing when extended. You will want to stick to 3 1/4" wheels though, otherwise you will be modifying the struts and also having some clearance issues when retracting gear.

michaelbbbb

Kempdawg,

I am in agreement with you and Old Bird on the retract bay needing to be beefed up even more. I fit birchwood pieces under both the front and back of the retract bay and epoxied them in place. This allowed me to use longer screws to attach the robart mechanicals (608hd) that I'm using. I have had no problems with retracts so far, and everything seems very solid.

Jonathan2121

Thanks michaelbbbb and corsairjock,

I ordered everything I needed today. I will be sticking with the 3 1/4" wheels to make my life easier.

Before I mount the retracts I will be beefing up the mounting bays with extra wood, lots of epoxy and fiberglass.

I am going away on vacation for 2 weeks so I won't be able to start the surgery. But I will keep you guys updated with some pics when I start.

Thanks

Jonathan2121

Does anyone have any photos of the landing gear doors attached to the robart struts and how did you attach them?

Thanks

CorsairJock

My Feedback: (90)

I am still awaiting delivery of a set of Robart part # 650DB: gear door mounts for use with 380 series/ 3/8" diameter RoboStruts. Tower says that they are temporarily discontiued. I just oreded a set from my LHS, and they say they can have them by Wednesday next week. As soon as I get them, I'll be using them to attach my gear doors. Until then, my RoboStruts are 'naked'.

Georg Matthews

My Feedback: (6)

If tower is out of stock then I bet your dealer can't get them either as one of his main sources for robart parts is Great Planes distributors and Great Planes and Tower a one in the same.
I would recommend going online and find a dealer that just may have them is stock.

michaelbbbb

I actually skipped putting the landing gear doors on mine....I always fly off grass fields, and I have found that the gear doors double as grass catchers/plane flippers if the runway isn't cut just so.....same reason I go without pants on my Extra 300....(BTW, I actually wear pants, just don't put them on the extra landing gear.. )

Georg Matthews

My Feedback: (6)

Well I made the first flights of my P-51 today and I am pretty pleased.
The only real problem I have had is one of the plastic retract housings cracked and broke.
All my landings where greased two wheel landings on a fairly smooth grass field.
The same field I made over 300 landings with my WM P-51 and I didn't have one not one gear problem.
Also I had an interesting thing happening today.
My TF P-51 doesn't seem to hold trim on the roll axis.
On my first flight I thought I needed to give her a click or two of left aileron trim. but then she started to roll slightly left without giving any trim changes.
What I am trying to say is that this bird doesn't hold a neutral aileron setting, it is constantly drifting both right and left slightly on the roll axis.
Any ideas ?
I am using Hitech Digital programable servos for the ailerons.

Jonathan2121

Should I go with the offset robart struts 653L and 653R

or

Robart 650 Straight RoboStrut 3/8"

is there a difference in performance. will either of them fit ok, without making modificatons?

michaelbbbb

The 653L and R is the way to go for both fit and scale reasons.

Jonathan2121

Thanks michaelbbbb

Jonathan2121

Does anyone have photos of how the pushrods are connected to the retract servo?

The_Russian

Does anyone have pictures of the Robart mechanical install? I just purchased the 608HD's and 653 L&R struts and have no idea how to set them up. This will be my first retract install to date so any help, pics, or tips are appreciated.

CorsairJock

My Feedback: (90)

SHOO SHOO BABY: COMPLETED at LAST! Well, still waiting for landing gear door brackets, and other small details, but all correct markings are on her.

harfordr

Has anyone tried to put a Zenoah G20ei (gasser) in one of these? Do you think it would fit?

michaelbbbb

I am using a Saito 125, and I wouldn't want to try and stuff a larger engine in this plane. The Zenoah looks nice for a large cowl plane like a P-47, but if you put it in this P-51, you might as well give up on having any cowl left to mount.
Plus you would be adding over 12 oz of extra weight to the nose. Mine is 10.5 AUW with the Saito, a slimline pitts and a smoke pump...so you
would go well over 11 lbs and still have to maybe counter weight to the rear of plane to get CG close to where it needs to be.

I don't see this airplane working out with the G20 too well.

CorsairJock

My Feedback: (90)

Amen. I can't understandstand why some want to save a few bucks in fuel costs SO MUCH, that they are willing to add about 2 lbs to total weight, and end up with a glorified weedwhacker/ chain saw sound. What is the point?
Some have pointed out that the landing gear/ retracts are suspect. Why add 2 more pounds to the weight, and in doing so: add even MORE stress to the retracts?
To each his own, but I just don't get it.

AirWizard

My Feedback: (3)

LoL!!!!!!!!!!

Some people might think the same thing about flying a P-51 that sounds like a mosquito

CorsairJock

My Feedback: (90)

Touche.

I'll be flying mine at the Warbirds Over Gilmore (classic car museum) near Hickory Corners, Michigan this afternoon:
http://www.kazoothunderbirds.com/events.htm

MAYBE I can get another video made, and MAYBE someone elsl will show up with another Top Flite Mustang

plopes

Hi,

Can anyone tell me which is the better retract?

Robart 550RS with 653 Robostruts. (air up/ air down)

Robart 700RS with 653 Robostruts. (air up/ spring down)

Lado 60-5 with 653 Robostruts. (electric)

Century Jet P51 with robostruts. (air up/ air down)

I am seriously unsure where to invest all that cash...

CorsairJock

My Feedback: (90)

The simple answer is no. Ask 10 people, you'll likely get 10 different answers. First off, you must define "better". Better in which way? Some are better looking, Some have a more realstic operation, some are more robust, some are more simple to install. When you decide that, I suggest that you begin a new thread, and post a it with a poll.

4 Blade Prop: Here are long awaited pics of my 4 blade prop (APC 14.4 x 11) installation. I think it is drawing about 35 amps with this prop, compared to 28 with the 2 blade (APC) 15 x 12. Despite the increased power, it seemed to fly better (had more pull during loops) with the 2 blade. I may end up using the 2 blade most of the time, and install the 4 blade for special occasions (like: warbird events)

Getting back to RoboStruts and retracts: the remaining 5 pics are of my LEFT SIDE retract. Some of you have been asking for details and/ or pics, so here they are. There are the stock retract units with RoboStruts installed, and 3 1/2" Dave Brown wheels. The 5 mm strut wires have been cut as short as possible, but note that I left the loop in and note it's orientation (inward). I like the added shock absobrtion that comes with leaving the wire loops in. By mounting the loops inward, the wheels are COMPLETELY retracted into the well, leaving plenty of room to mount those gear doors (IF you can locate the appropriate Robart gear door brackets).

Like I said earlier: I do not recommend using RoboStruts with the stock retracts because to modify the RoboStrut inserts is too complicated for most of you. They must be bored to 5mm.
If you want to install RoboStruts, regardless of whether you use the stock, Robart, or other: IF you want to retain the loops as I did, you will need to make the strut wire as SHORT AS POSSIBLE where it inserts into the retract trunion. This is because the offset RoboStruts can only be shortened so much, and you will also have to make them as short as possible.
I'm gonna guess that most of you however, will choose to remove the wire loops. This will not only simplify the installation, it will make it better looking also.