---------------------------------------------------------- RV9-List Digest Archive --- Total Messages Posted Thu 05/25/06: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:03 PM - Re: Aft CG (Chenoweth) ________________________________ Message 1 _____________________________________ Time: 02:03:18 PM PST US From: "Chenoweth" Subject: Re: RV9-List: Aft CG --> RV9-List message posted by: "Chenoweth" I'm planning to get the strobe from Van's and I think it's the same power supply I have in the Kitfox. I'm expecting it will fit since my 7A neighbor has one in about the same place. ----- Original Message ----- From: "Bill Repucci" Sent: Wednesday, May 24, 2006 9:45 PM Subject: RE: RV9-List: Aft CG > --> RV9-List message posted by: "Bill Repucci" > > Careful on the strobe you order, some of the strobe packs are so large > they will not fit under the floor. The one I have is from these guys: > http://www.airplanegear.com/skybright.htm. It is basically an > automotive unit. Small, light, and simple. > > Bill > > -----Original Message----- > From: owner-rv9-list-server@matronics.com > [mailto:owner-rv9-list-server@matronics.com] On Behalf Of Chenoweth > Sent: Wednesday, May 24, 2006 7:07 PM > To: rv9-list@matronics.com > Subject: Re: RV9-List: Aft CG > > > --> RV9-List message posted by: "Chenoweth" > > Bill, > I appreciate the info and your time in providing it. I'm going to order > the ELT and Strobe 6 from Van's soon and will follow your example. Bill > C. do not archive > ----- Original Message ----- > From: "Bill Repucci" > To: > Sent: Tuesday, May 23, 2006 10:44 AM > Subject: RE: RV9-List: Aft CG > > > > --> RV9-List message posted by: "Bill Repucci" > > > > Bill, > > > > Regarding the G loads, I did not give it any consideration. The ACK > > ELT > > (http://www.aircraftspruce.com/catalog/avpages/ack_tech.php) that I am > > using is bolted to the baggage compartment rib, not the bottom skin. > > The idea was to keep it from vibrating on the bottom skin. I don't > know > > if this will work or not, time will tell. My tech advisor did want me > > to move it to on top of the baggage compartment floor so it is > > accessible in the case of an accident. I have elected to leave it > under > > the floor but will use thumb screws so I can access it in the event of > > an accident. > > > > >From what I've been reading, most of the accidents that trigger the > > >ELT > > are such that the passengers don't survive so I'm not really too > > worried about it's placement. One thing nice about having it under > > the floor, if I do get into an accident, it will most likely not > > become a projectile. > > > > A side note to this, after placing it there and running the phone line > > > and antenna wire through the other floor ribs it was pointed out to me > > > that certified aircraft try not to run these wires through ribs > > because in the event of an accident the rib can cut the wires. Just > > another thing to consider when you select your placement. I'm not > > sure if the phone wire that goes to the control switch is that > > critical but I suspect it could be cut in such a way so as to > > deactivate the ELT, again, I'm not really sure about this. > > > > If I had to do this over again, I doubt I would include the hinges, > > just use the screws to hold the tops in place. I had extra hinge > > laying around and used it, which is just like me to make it more > > difficult to build. > > > > As I said above, the ELT tray is bolted to the side of the floor rib > > with 8-32 plate nuts. The lids were made from an extra tank skin I > > had laying around (don't ask). > > > > The strobe light power supply was similar in construction, only I > > bolted it to the lid itself. Again, in an effort to keep from > > mounting anything directly to an outside skin. Someone once told me > > not to mount anything to an outside skin because the flexing of the > > skins could cause stress cracks. This may be an old wives tail, I > > don't really know. > > > > Bill > > > > -----Original Message----- > > From: owner-rv9-list-server@matronics.com > > [mailto:owner-rv9-list-server@matronics.com] On Behalf Of Chenoweth > > Sent: Tuesday, May 23, 2006 8:55 AM > > To: rv9-list@matronics.com > > Subject: Re: RV9-List: Aft CG > > > > > > --> RV9-List message posted by: "Chenoweth" > > > > Bill, > > That's very persuasive so I guess I'll head in that direction. I had > > a look at your pictures - nice job. A few questions: Was there any > > particular reason you hinged the doors? Did you feel it necessary to > > consider the G loads the ELT would suffer in a crash and beef up its > > mounting accordingly? It doesn't look like the Ameri-King ELT? Is it > > 406 MHz Artex? If not, did you make any provision for switching when > > the time comes? Could you describe the way the sides of each bay are > > done - material and attachment? And again, thanks for the help. Bill > > C. > > > > ----- Original Message ----- > > From: "Bill Repucci" > > To: > > Sent: Sunday, May 21, 2006 9:37 PM > > Subject: RE: RV9-List: Aft CG > > > > > > > --> RV9-List message posted by: "Bill Repucci" > > > > > > Bill, > > > > > > As for the placement of items behind the 706 bulkhead, I would still > > > > be careful. I put both the strobe power supply and ELT under the > > > baggage compartment floor using access doors. This will allow me to > > > > rivet the floor in place. > > > > > > I suspect the reason Van's wants both the baggage floor and seat > > > pans riveted in place is to make them act like a box structure as > > > there is a lot of loads going through those items. However, there > > > are a good number of planes flying with them screwed in place. > > > > > > My -9 will have them riveted in place for two reasons. 1st, I'm > > > lazy and that is a lot of plate nuts. 2nd, I'm trying to make my -9 > > > > as light as possible and those plate nuts and screws add a good bit > > > of weight. > > > > > > The reason for putting the ELT and transponder under the floor is > > > also > > > > > twofold. 1st, it gets more weight out of the tail so I can avoid > > > any potential CG problems. (Even though I doubt I will have any.) > > > 2nd, an > > > > > airplane with all the weight in the center handles better. > > > > > > Here is a picture of where I put my ELT: > > > http://www.repucci.com/bill/images/elt%20with%20door.jpg > > > > > > And here is the location of my strobe power supply: > > > http://www.repucci.com/bill/images/strobe%20power%20pack.jpg > > > > > > Good luck, > > > Bill > > > > > > -----Original Message----- > > > From: owner-rv9-list-server@matronics.com > > > [mailto:owner-rv9-list-server@matronics.com] On Behalf Of Chenoweth > > > Sent: Sunday, May 21, 2006 6:21 PM > > > To: rv9-list@matronics.com > > > Subject: Re: RV9-List: Aft CG > > > > > > > > > --> RV9-List message posted by: "Chenoweth" > > > > > > Bill, > > > Great info and thank you very much. > > > The fellow I asked at Van's was singularly un-helpful with this. > > > His response was to not worry about the CG and if it came out too > > > far aft use a metal propeller. Sort of missed my point about > > > wanting to use a > > > > > wooden one and provided absolutely no ideas about where/how to > > > locate things like ELT. strobe power supply, etc, farther forward. > > > Was pretty adamant about not making the baggage area floor > > > removable, though. I conclude from what you said that I should have > > > no problem if > > > > > I go ahead and mount the ELT and all just behind the 706 bulkhead > > > and, > > > > > absent anyone commenting to the contrary, I think that's what I'll > > > do. > > > > > Bill C. > > > > > > ----- Original Message ----- > > > From: "Bill Repucci" > > > To: > > > Sent: Sunday, May 21, 2006 3:09 PM > > > Subject: RE: RV9-List: Aft CG > > > > > > > > > > --> RV9-List message posted by: "Bill Repucci" > > > > > > > > Bill, > > > > > > > > Check with Van's to verify what I'm about to say. > > > > > > > > >From what I have read the RV-9 does not seem to have the same aft > > > > > >CG > > > > issues as the -7A. I have played around with sample loadings > > > > while moving the CG for and aft as much as 2" on the -9 and found > > > > everything > > > > > > > is good. > > > > > > > > I suspect this is because of the RV-9's wing. Meaning that it is > > > > longer and thus more of it is forward of the CG. > > > > > > > > Also, on TW RV's there is less weight aft of the CG than on the A > > > > models. A's have the main gear and steps aft of the CG where we > > > > only have the TW, granted it is WAY back there but it still > > > > doesn't seem to > > > > > > > be an issue as it is offset by the heaver engine mount (two gear > > > > legs > > > > mounts) and the gear legs and wheels them self way in front of the > > CG. > > > > > > > > Van's also compensates a bit with a slightly longer engine mount > > > > for > > > > > > the -9's. I know the one I have and the cowling are sized > > > > (extended) for the O-235. This will help out with the Catto > > > > wooden prop I have sitting on my shelf. > > > > > > > > That is what I am hoping for as I'm putting a lighter engine in my > > > > > -9 (O-290-D2). As a side note, I exchanged some emails with a > > > > gentleman out West who has the same set up and he simply said not > > > > to > > > > > > worry about > > > > > > > the CG as it isn't a problem. > > > > > > > > To verify this, check Dan C's site (www.rvproject.com) and play > > > > around > > > > > > > with his CG calculator. Granted, there are no -9's on the list, > > > > only -9A's but you will get an idea of how the CG comes out. > > > > > > > > Hope that helps. > > > > Bill R. > > > > www.repucci.com/bill/baf.html > > > > > > > > -----Original Message----- > > > > From: owner-rv9-list-server@matronics.com > > > > [mailto:owner-rv9-list-server@matronics.com] On Behalf Of Michael > > > > T. > > > > > > Ice > > > > Sent: Sunday, May 21, 2006 10:50 AM > > > > To: rv9-list@matronics.com > > > > Subject: Re: RV9-List: Aft CG > > > > > > > > > > > > --> RV9-List message posted by: "Michael T. Ice" > > > > > > > > Bill, > > > > > > > > I have the same concerns. I do plan on installing a larger > > > > tailwheel > > > > > > assembly. Although I am not planning on using a wooden prop I do > > > > plan on > > > > > > > > installing the elt and the strobe power packs farther forward. > > > > > > > > It would be interesting to see what others think or have done? > > > > > > > > An answer to your concerns would be to insulate both the firewall > > > > and front floor heavily. > > > > > > > > Mike Ice > > > > Anchorage, Alaska > > > > RV-9 Fuselage, installing wings for the first time > > > > ----- Original Message ----- > > > > From: "Chenoweth" > > > > To: > > > > Sent: Saturday, May 20, 2006 2:24 PM > > > > Subject: RV9-List: Aft CG > > > > > > > > > > > > > --> RV9-List message posted by: "Chenoweth" > > > > > > > > > > This is a question for any of you with a completed tailwheel 9. > > > > > I'm > > > > > > > > in the tail cone and mid section construction part of one and > > > > > wonder > > > > > > > > about CG problems. I'm hoping to use a wooden prop and worry > > > > > that > > > > > > > I'll end up with a very aft CG if I do. That is leading me to > > > > > wonder if ELT and strobe power supply placement should be other > > > > > than > > > > > > > > behind bulkhead 706 (which is where Van's strongly recommends I > > > > > put them). Any comments and suggestions on this will be > > > > > gratefully > > > > > > > received. Bill Albion, Maine > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >