July 27, 2022 at 8:20 pm #182843
Good laugh. I’m preparing to start a Rareliners/ATP Metro kit. I built one way back when. How much nose weight to add? At least the instructions say to add weight which is a data point. If I was Superman I could look inside and see how much weight I used last time. If I was a doctor or dentist I could take an X Ray. Since I’m none of the above I’ll do the old cut out the parts and assemble with blue tape routine instead. Easier said than done for a 1/144 scale commuter plane.
Edit your Profile to get a forum signature.July 27, 2022 at 11:29 pm #182844AhmedPosts: 2,043Location: Sunny CaliforniaOccupation: Software Engineer
I’m not sure why everyone seems to get hung up on exact grams and ounces. What’s the problem with adding a lot more than you think is needed? Just be on the safe side. 🙂
KSFOJuly 27, 2022 at 11:45 pm #182845radioguyPosts: 699Location: CYUL
I agree with Ahmed. It’s not like the CoG is of major importance. The 2 criteria are that the weight must prevent the kit from tail-sitting, and not cave the nose gear.
Where there's a will, there's a relative.July 27, 2022 at 11:57 pm #182847
I agree that the amount of weight isn’t critical other having enough +5% so the model isn’t a tail sitter. I have at least one model where the weight has broken loose so I can adjust the CG and have it either sit on the tail or on the nose gear. Just wish I could remember what I used and how much last time 🙂
Edit your Profile to get a forum signature.July 28, 2022 at 3:52 am #182850LH707Posts: 1,528
Well, if you want to get nerdy, just do a weight/balance. Tape it all up, measure CG, then determine CG shift needed and back out the weight needed, then add more in case you were a bit wrong.
Edit your Profile to get a forum signature.July 28, 2022 at 6:12 am #182851gebbwPosts: 727
I hear ya Ken, it weighs on your mind… 😀
AKL NZAugust 23, 2022 at 3:56 pm #183059HighlanderPosts: 12
If in doubt, I use a simple home made jig from a flat piece of scrap wood. Drill 3 holes to correspond with the model’s nose and main undercarriage attachment points and sit the model loosely on the jig with the stablisers (tailplanes) and anything else which may affect the trim, like rear fuselage mounted engines, taped in position if not glued by this stage. Scrap sprue the same diameter as the holes drilled make perfectly good temporary legs. Add weight until it sits right. Usually works pretty well. If it’s an SD-360, DHC-6 Twin Otter or Saab 340 you can always cheat and use a ‘pogo stick’ which is a simple anti tip safety device employed on the real aircraft. Basically just a strong metal rod which is loaded in the rear cargo hold and always stays with the aircraft and which clips to a point below the rear fuselage. Just remember to board your front cabin seated passengers first and have them disembark last and offload the aft holds before the forward ones! The BAe ATP, Airbus A320 and 737-400 always used to require extra care when loading. You can adapt the jig to other aircraft simply by drilling new holes for the main gear.
Edit your Profile to get a forum signature.August 23, 2022 at 10:42 pm #183060
Thank you for the encouragement Highlander. I had to re-read your post. At first glance I thought the suggestion was to re-drill holes for the landing gear struts. Certainly a way to adjust weight/balance but likely not the best way 🙂
Just remember to board your front cabin seated passengers first and have them disembark last and offload the aft holds before the forward ones! The BAe ATP, Airbus A320 and 737-400 always used to require extra care when loading. You can adapt the jig to other aircraft simply by drilling new holes for the main gear.
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