Show your stuff
03-12-2015, 10:19 AM
#126
X's two on having nuts. Over time the vibration will destroy the threads on the push rod at the clevis. (there is a bad joke in there somewhere)
As for the firewall. I like to add some cloth either inside or outside of the firewall. Especially if you are installing a 120SC on the nose.
Wing. I like to use cloth top and bottom of the wing. Glass where the fuse touches the wing on top and on the bottom glass out to the retracts. Additionally, check the retract rails and add glue... they usually fail.
Jimmy Skids
As for the firewall. I like to add some cloth either inside or outside of the firewall. Especially if you are installing a 120SC on the nose.
Wing. I like to use cloth top and bottom of the wing. Glass where the fuse touches the wing on top and on the bottom glass out to the retracts. Additionally, check the retract rails and add glue... they usually fail.
Jimmy Skids
03-12-2015, 09:40 PM
#127
Thanks everyone one for the advice. I feel a whole bunch better of ground control of the plane!
I have 2 more questions
one mentioned about the metal clevis on the surfaces, to fix do I just put a nut butted up against the clevis? Or Should I change them all to plastic?
also one of my previous photos showed the inside of fuselage with the glue on firewall. Does it look like there is enough glue on the firewall? Do I need to pin the firewall - what does that mean and what does that look like?
do I need to glass the wing 3-4"? I doesnt look like it is.
thanks gerald
Gerald,
Yes, just a basic nut tightly snugged up against the metal clevis. I would stay with the metal clevis at the speeds you want to go.
Regarding the glue: having seen these race engines seize causing the nose section snap off of other pilot's planes probably 3 or 4 times now, while you likely have enough glue at the joint, I always choose to go above and beyond to reinforce the nose section, and recommend you do as well. Like Skids, I prefer fiberglass; but I like to add tri-stock where possible to not only get more reinforcement on the joint, but it makes the fiberglass easier to lay down properly around that tight corner. (Two 45-degree angles, rather than one 90-degree angle.) All that glue on the back of the firewall and sides, however, means that tri-stock is not going to be a very realistic option for you on this one. One other option might be a U-shaped piece of plywood reinforcing the firewall's connection to the fuse sides. This is what the install looked like when I used one to reinforce the P-39 I detailed building the "Trinity-build" thread. This was in post #216 on page 9 of that thread. The P-51 build with the tri-stock I added to my firewall is pictured in some posts on page 15; and, I guess I am too late with the information now, but somewhere within a page or two of this is my steerable tailwheel installation on that plane.
I have seen some modelers pin the firewall, as you mentioned. Think of this as a dowel joint. The way I have seen it done is to drill holes (perhaps a half inch or so apart) through the fuse sides and into the firewall. Add epoxy and insert a bamboo barbecue skewer or small diameter dowel seated into each hole. Then trim, sand and recover.
I ALWAYS fiberglass the center section of ALL my wings. How much depends on other reinforcements . . . is there a dihedral brace & how substantial? . . . Are the spars spruce, or just balsa? How solid does the glue joint look at the center section? (Beings you are not the original builder, this could be important -- I've seen some horrible looking joints from other builders over the years, with large gaps and little glue, so definitely check this.) The WM Mustang ARF comes stock with a dihedral brace . . . the question is whether or not to assume the original builder installed it. If so, and all else looks good, my Mustangs have held together using two strips of 3" center section FG reinforcement tape, with each strip overlapping 1" on each side of the center section. This would likely be fine for Silver, but if you intend to go faster, and/or do not want to take any chances, definitely follow Skid's recommendation and go out further.
Hope this helps.
Ollie
Last edited by Iron Dog; 03-12-2015 at 10:16 PM.
03-13-2015, 01:48 PM
#128
Everyone has their opinions bsed on 1). common sense 2). their own experiences 3). others advice based on their experiences
My advice- listen to all 3 as you will one day experience all of them yourself if you compete long enough.
All the above are good ideas, some may be over kill, but still totally valid considering the power plant you have on this plane.
Ill see you in PHX in a couple weeks and hope all goes well for you.
My advice- listen to all 3 as you will one day experience all of them yourself if you compete long enough.
All the above are good ideas, some may be over kill, but still totally valid considering the power plant you have on this plane.
Ill see you in PHX in a couple weeks and hope all goes well for you.
03-13-2015, 05:03 PM
#129
Everyone has their opinions bsed on 1). common sense 2). their own experiences 3). others advice based on their experiences
My advice- listen to all 3 as you will one day experience all of them yourself if you compete long enough.
All the above are good ideas, some may be over kill, but still totally valid considering the power plant you have on this plane.
Ill see you in PHX in a couple weeks and hope all goes well for you.
My advice- listen to all 3 as you will one day experience all of them yourself if you compete long enough.
All the above are good ideas, some may be over kill, but still totally valid considering the power plant you have on this plane.
Ill see you in PHX in a couple weeks and hope all goes well for you.
Just to be clear, I'm certainly not stating, or even implying, all these are necessary, just trying to answer your specific questions and give you options of methods you might choose towards rectifying any specific concerns. For example, I have never personally chosen to pin a firewall (as I have other preferred methods), but beings you asked what the technique was, I explained it.
Modelers continually argue over "Building to fly vs. building to crash" . . . light enough to optimize flight performance or building heavily enough to survive less than perfect landings and other stresses. Racing is no different; with everyone trying to find that elusive, magically perfect compromise of these opposing attributes. What compromises you ultimately choose depend on your particular piloting and building skills and preferences. Just know that we are always here, and happy to help.
Ollie
03-14-2015, 03:33 PM
#131
Those 3 Macchi looks really nice!
I was able to do my shakedown flight this afternoon that went really well. Plane flys pretty smooth. I didn't get to glassing the wing or over beefing up the firewall yet. I will try and complete before the AZ race. I flew my yellow mustang on a ys120 at the rabbit dry lake bed in CA. I used a
4x12 with 20% nitro. The motor takes a while to come up (maybe diaphragm valve open too much) but a after going full throttle for 30 seconds or so the motor comes up. The top speed was 123 mph according to the onboard GPS. So hopefully it will be ok for silver once I increase the nitro and prop it right. I think maybe 14x14, 13x13, or 13.5x13.5, but I will have to practice with that. I am shocked to feel the vibration of the motor tuning on the ground. Rough stuff. Thanks everyone for the advice thus far! 
gerald
I was able to do my shakedown flight this afternoon that went really well. Plane flys pretty smooth. I didn't get to glassing the wing or over beefing up the firewall yet. I will try and complete before the AZ race. I flew my yellow mustang on a ys120 at the rabbit dry lake bed in CA. I used a
gerald
03-14-2015, 04:00 PM
#132
Gerald
Glad it went well out at Rabbit.
Thats a good place to test planes for sure.
All YS engines need the proper time to "pressurize". Never get in a hurry going from idle (when first started up) to full throttle. Ill take as long as a minute.
Once you put 30 -50 percent in that thing with the right prop you will be fine.
There is so much power coming out of these YS engines that I always opt to run the hyde soft mount. Others on here will disagree and will say they lose rpms, which I wont argue, but the gain is worth it. My airframes love the effects of the soft mount.
Central Hobbies has these mounts if you are interested.
Glad we have you on board.
Glad it went well out at Rabbit.
Thats a good place to test planes for sure.
All YS engines need the proper time to "pressurize". Never get in a hurry going from idle (when first started up) to full throttle. Ill take as long as a minute.
Once you put 30 -50 percent in that thing with the right prop you will be fine.
There is so much power coming out of these YS engines that I always opt to run the hyde soft mount. Others on here will disagree and will say they lose rpms, which I wont argue, but the gain is worth it. My airframes love the effects of the soft mount.
Central Hobbies has these mounts if you are interested.
Glad we have you on board.
03-14-2015, 04:23 PM
#133
After looking more closely at your pics I would suggest:
1). beef up the fire wall with triangle stock
2). What size fuel tank is that? Id say you need a minimum of a 16 oz.
3). if you do run higher nitro, Id glass the center section of the wing and sheet the stab
now that you know it flies, Id take care of it properly.
1). beef up the fire wall with triangle stock
2). What size fuel tank is that? Id say you need a minimum of a 16 oz.
3). if you do run higher nitro, Id glass the center section of the wing and sheet the stab
now that you know it flies, Id take care of it properly.
03-14-2015, 04:23 PM
#134
After looking more closely at your pics I would suggest:
1). beef up the fire wall with triangle stock
2). What size fuel tank is that? Id say you need a minimum of a 16 oz.
3). if you do run higher nitro, Id glass the center section of the wing and sheet the stab
now that you know it flies, Id take care of it properly.
1). beef up the fire wall with triangle stock
2). What size fuel tank is that? Id say you need a minimum of a 16 oz.
3). if you do run higher nitro, Id glass the center section of the wing and sheet the stab
now that you know it flies, Id take care of it properly.
03-16-2015, 09:26 AM
#143
I understand and there are very few qm40's that even have the partial cheek cowl like yours has. Even yours is not a full cheek cowl like the formula ones had. The Ashley, Loki, vendetta, miss Candace, etc all have totally exposed engines like mine shows. Yours is one of few, I think the polecat, sweet v, and rivets have the partial cowl like yours. Is yours a rivets?
03-16-2015, 09:27 AM
#144
I understand and there are very few qm40's that even have the partial cheek cowl like yours has. Even yours is not a full cheek cowl like the formula ones had. The Ashley, Loki, vendetta, miss Candace, etc all have totally exposed engines like mine shows. Yours is one of few, I think the polecat, sweet v, and rivets have the partial cowl like yours. Is yours a rivets?
