How to fight the sag?

[Sabrefan]

I put my BBI Blackhawk on my top shelf when I first got it. I took it down today, and I noticed the rotor blades are really starting to sag bad. Anyone thought of a way to fix this problem? I am thinking maybe some strong clear tape under the blades, but I have not tried anything yet. It is such a nice model, I hope I can think of a way to keep the blades from sagging to bad.

[Moth]

Problem?
That's not a problem, it's an undocumented feature (old computer joke)

The blades on real helicopters also sag, maybe a bit less, but they do sag significantly nonetheless.

Now how to make them all sag evenly is a problem. The only thing that has worked for me, although it is temporary (stays that way for about 6 months, untill you do it again), is to heat up the blade that's different with a hair dryer, and let it cool in the position that you need it. (in my case, only one blade was sagging less than the others)

[tmanthegreat]

I think there's been some interesting solutions over the years and hopefully they'll be posted. Thinking quickly about your problem, however, it may be possible to attach a wire underneath the blade that could help shore it up. Painted black, the wire wouldn't show at a distance. It would have to be a heavy-gague wire, like that from a wire coat hanger and you would have to bend it carefully to stick to the shape of the rotorblade. Not sure how you could attach the wire to the base of the rotor, but it seems like it might work

[Threetoughtrucks]

So, I see the of this thread title and I have a whole different vision of what this thread is about.....

Sorry, I'll just go back to my exercises.......

TTT

[Sabrefan]

[aferguson]

the best solution is just to resign yourself to rebending them with a blow dryer every few months. If you overbend them a bit, passed where you ideally would like them, that will buy you extra time. Really heat them hot, so they are very soft, bend and hold under cold water for a long time, so there is no chance they are still warm inside.

I did my Apache a few years ago and haven't needed to re-do it yet. The blackhawk may have softer or heavier blades....i wait til it gets pretty bad and then spend an hour rebending them.

[sluff]

In my opinion, the blades look better sagging, I fuel Blackhawks and I can almost touch the tips of the rotors. The sag adds more realism to them, I have seen the Il. ANG add weights to their Blackhawks and Chinooks rotors to make them sag even more so they can hold them while wing walking.

[Spudkopf]

In my opinion, the blades look better sagging, I fuel Blackhawks and I can almost touch the tips of the rotors. The sag adds more realism to them, I have seen the Il. ANG add weights to their Blackhawks and Chinooks rotors to make them sag even more so they can hold them while wing walking.

I agree that for the most part the sag is quite acceptable for those (like myself) who display their choppers as if on the ground, but not so good for those who chose to hang theirs for an in flight display or simply due to lack of space it is a bad look.

The sag unfortunately seems to be a issue caused by the plastic BBI uses, as I have a 1/6th AH-6 with a much larger rotor diameter that is a good 8 or so years old and it blades are still quite straight, there also appears to very little or no sag in either the Huey or the Cobra.

As far as thinking about a solution I have always thought that cutting new blades from balsa wood or fibre like the RC choppers use could be a way to solve the problem, you could even try and find a suitable set of RC blades of a simular cord and cut and re-glue the tips to get the desired blade shape.

[ostketten]

Hang your copter upside down for about 6 months.

[Jesse James]

If you hang your copters from the ceiling, I'd suggest a thin, strong, steel rod that from one rotor tip to the other, and then the same on the crossing rotors... Some black electrical tape on the ends shouldn't show too, too much, and it would fix the unfortunate sagging issue.

If the blades were thicker one could try inserting a steel rod, but that would be quite difficult. The plastic used is for, ironically, durability of all things... Unfortunately it's a catch 22.

[jeffrowse]

As a thought, you could always just remove the blades entirely since you can't see them when spinning anyway.
I've got my birds sat on shelves with the rotors off anyway as it takes up less space that way... less likely for little (nephews') fingers to grab or for bodies (little or large) to knock them down (except the Cobra as that sits nicely along the shelf it sits on).

A trick I used on a couple of 1/72 kits was to fit a clear plastic disk of the right (or thereabouts) diameter on the top of the rotormast and paint a narrow band around the edge with 'clear' Tamiya yellow acrylic (used for the inside of car lights, usually!) to represent the hazard bands on the real thing. Not quite so practical for 1/18th as the plastic would need to be quite thick to prevent it sagging too.

If you really want to have the blades attached, just turn them upside down and say the heli is climbing - most helis have a noticable down-in-the-middle cone when climbing vertically or pulling gee.

[chaffhappy]

I was just going to say, "flip the blades upside down for a few days and just enjoy the implied flight maneuver until they straighten out." Rinse, repeat. The only problem I can't help wondering is whether that just stresses the plastic in the other direction, making it even more susceptible to sag, in a shorter amount of time. But I keep my displays in the basement of the house, where it's much cooler and summertime heat doesn't have as large an influence to the plastics.

For me, sagging blades is a mild concern because of the motors I've been putting in to make them spin for display purposes. Not RC flying engines, just moderate electric motors. Too much droopiness and the blades are a little uneven and unpredictable when they start up. It's more comical a problem than critical, but I can be quite particular with the appearance.