Q2/200 Engine mounts


Ian Ashdown
 
Edited

Does anyone have a dimensioned drawing of the Q2EM1 O-200 Engine Mount/Spacer that they’d share?  Failing that, the distance the space the engine forward?

I’d download the Metal Part CAD of Canard Zone, but this part appears not to be part of the list offered.

Thanks, 

Ian


Jay Scheevel
 

Page 82 in the following linked document has a scale drawing of the mount pillar. Should be sufficient to build from. 

 

Cheers,

Jay

http://n8wq.scheevel.com/documents/Q2_Q200_Plans_Abridged_for_Scheevel_Construction.pdf

 

 

From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Ian Ashdown
Sent: Sunday, February 6, 2022 11:53 PM
To: main@Q-List.groups.io
Subject: [Q-List] Q2/200 Engine mounts

 

[Edited Message Follows]

Does around have a dimensioned drawing of the Q2EM1 O-200 Engine Mount/Spacer that they’d share?  Failing that, the distance the space the engine forward?

I’d download the Metal Part CAD of Canard Zone, but this part appears not to be part of the list offered.

Thanks, 

Ian


Ian Ashdown
 

So I have the Engine and Firewall in CAD and I'm trying to establish the position/orientation of the engine.



Do these aircraft offset the engine in any way?  Nose down?  Aligned to the left?

I have found some documentation that says the O-200 Thrust Line is 7.6" from the top of the Firewall and as a starting point I'm going to use that same number, but from a packaging point of view it could really be a little higher, perhaps by 1.6".  Do we think this would put the aircraft out of trim?  Would the higher thrust line have any negative affects?

This is why we do the drawing!!

Ian


Chris Walterson
 

Ian------------  I am pretty sure there is a fellow in Sweden, or some Nordic country that has already installed a 912 in a Q2. He may be a wealth of info. Can't remember his name , but he was there when we did the video about my airplane.

 Easier to follow a path then break trail.  Take care-------------  Chris


--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus


Ian Ashdown
 

That is great to know that it's been done before!  Good to know there is at least one other person who thinks this might be a good idea . . . 

I would love to make contact with him, I'm sure he could save me chasing all kinds of wrong-headed ideas!

If anyone can but a name to this chap I'd definitely like to make contact.

Ian


Michael Dunning
 

I checked the copy of the metal parts files I bought last week and can confirm the engine mounts are NOT contained in any of the drawings. Bummer. 
--
-MD
#2827 (still thinking about planning on visualizing how to finish building)


Jay Scheevel
 

I think the drawing that I sent you the link for should be sufficient to create a Cad model for fabrication. They are not complex or high tolerance parts.

Cheers,
Jay


On Feb 9, 2022, at 6:58 PM, Michael Dunning <dunningme@...> wrote:

I checked the copy of the metal parts files I bought last week and can confirm the engine mounts are NOT contained in any of the drawings. Bummer. 
--
-MD
#2827 (still thinking about planning on visualizing how to finish building)


Ian Ashdown
 

I bought that download too.  I’m sure it’ll be useful at some point.  What is slightly aggravating is that the parts were obviously modeled in SolidWorks, so why not offer a SolidWorks  or .stp download.  I’d have paid a little more for that, but now I just have to model the parts all over again . . . in SolidWorks!

In the end I think the design of engine mounts are going to be driven by the type of AV Mount I select ( does anyone have any recommendations) and the spacing off the firewall, driven by the balance of the lighter engine.  I’m still not sure if the effect of moving CofG a few points rearward would be a positive or a negative.  I think negative as pilot, passenger and ‘luggage’ are all aft of the CofG, it may limit the max load capacity.

Then there is the question of the ‘thrust line’. I think I’d like to raise it (from the O-200 WL position)  for better packaging, but I’m not certain yet.  Would raising the thrust line 1”- 1.6” create handling issues?  I don’t know what the aircraft vertical CofG height is, maybe it’s in some of the documentation . . .

Lots to figure out!

Ian
SoCal


Jay Scheevel
 

My feeling is that the vertical CG and by association the center of thrust are not critical in affecting the handling or stability. I say this because the Tri-Q adds a good 50 pounds well below the aircraft center and still handles much like the tail dragger. Also, from my experience, best to keep the flying CG closer to the front of the envelope than the rear. My 2 cents.

Cheers,
Jay Scheevel, Tri-Q2 N8WQ, 201 hours 


On Feb 9, 2022, at 7:28 PM, Ian Ashdown <ian.ashdown@...> wrote:

I bought that download too.  I’m sure it’ll be useful at some point.  What is slightly aggravating is that the parts were obviously modeled in SolidWorks, so why not offer a SolidWorks  or .stp download.  I’d have paid a little more for that, but now I just have to model the parts all over again . . . in SolidWorks!

In the end I think the design of engine mounts are going to be driven by the type of AV Mount I select ( does anyone have any recommendations) and the spacing off the firewall, driven by the balance of the lighter engine.  I’m still not sure if the effect of moving CofG a few points rearward would be a positive or a negative.  I think negative as pilot, passenger and ‘luggage’ are all aft of the CofG, it may limit the max load capacity.

Then there is the question of the ‘thrust line’. I think I’d like to raise it (from the O-200 WL position)  for better packaging, but I’m not certain yet.  Would raising the thrust line 1”- 1.6” create handling issues?  I don’t know what the aircraft vertical CofG height is, maybe it’s in some of the documentation . . .

Lots to figure out!

Ian
SoCal


Michael Dunning
 

Thanks for the info, Jay. Nice to have additional data points.

Ian,
I have a thread over on the Q-Performance list talking about some possible alternative engines. I have the same question, since oddly enough the Aeromomentum engines want to be an extra 1.5 inches down from the O-200 location in order to maintain the stock over-the-nose sightlines.

I have not seen a vertical C.G. documented anywhere in the plans. However, the Q-200 plans specifically mention placing the thrust line on W.L. 15, which does not correspond to any other jigging or mold lines... I can only infer that W.L. 15 may in fact be the as-designed vertical CG, but we will likely never know. 
--
-MD
#2827 (still thinking about planning on visualizing how to finish building)


Ian Ashdown
 

I don’t believe the design O-200 thrust line is WL 15” but the only dimensional reference I’ve found states that it is 7.6” (I think) from the top of the firewall.  Don’t you love the use of consistent datum’s!  My question is, is that the firewall panel (inside of the Fuse) or the outside of the fuse at the FS 14” (firewall)?

Very confusing/frustrating!

Ian
SoCal


Jay Scheevel
 

I computed the vertical position of my empty CG when I was doing my weigh and balance by changing the angle of the fuselage from zero and recording the difference in scales and FS’s, then computed the vertical CG from those. I will see if I can dig that up. I also did a measurement of the difference between the thrust line of the Revmaster and the O200. They are not the same. Will see if I can find that also. 

Cheers,
Jay


On Feb 9, 2022, at 9:03 PM, Ian Ashdown <ian.ashdown@...> wrote:

I don’t believe the design O-200 thrust line is WL 15” but the only dimensional reference I’ve found states that it is 7.6” (I think) from the top of the firewall.  Don’t you love the use of consistent datum’s!  My question is, is that the firewall panel (inside of the Fuse) or the outside of the fuse at the FS 14” (firewall)?

Very confusing/frustrating!

Ian
SoCal


Michael Dunning
 

I also did a measurement of the difference between the thrust line of the Revmaster and the O200. They are not the same. Will see if I can find that also.

I just posted it a couple of days ago: Revmaster and O-200 Thrust Lines. Still an open question on the inclusive vs. exclusive of fuselage thickness until I get out to the hangar, though. The Q-200 firewall Appendix sheet seems to include the fuselage thickness while the Q2 plans say to place the Q2 firewall template inside the fuselage shells; both firewall templates have the same OML dimensions...
--
-MD
#2827 (still thinking about planning on visualizing how to finish building)


Ian Ashdown
 

Yes, exactly!  The inconsistencies are difficult to navigate!


Ian Ashdown
 

You did indeed!  And it was helpful.  But there is still some doubt about the datum’s.  I’m going to try some things to see if I can get some better guidance.

Ian


Ian Ashdown
 

Jay,

Ive done vertical CofG calculations on race cars the same way.  Unfortunately I don’t have a physical aircraft to work from, just some empirical data and calculations.

I feel reasonably comfortable that the thrust line +/- 1” or so should not change the characteristics too much.  I’m going to go forward designing the engine mounting system based on the best packaging.  The standard Rotax silencer is quite large, maybe re-designing something a bit flatter would allow me to lower the engine closer  to the O-200 thrust line.

Ian


Mike Dwyer
 

FYI, I needed to place a 24 lb battery (PC925), behind the first bulkhead in the rear shell.  So the Q200 is very nose heavy as built.  It would be better to use a smaller battery closer to the front to save overall weight.  
On the motor mounts... To fit on the firewall the square base had to be modified anyway so this is not a precision part by any means!
Mike Dwyer Q200


On Wed, Feb 9, 2022, 9:58 PM Jay Scheevel <jay@...> wrote:
My feeling is that the vertical CG and by association the center of thrust are not critical in affecting the handling or stability. I say this because the Tri-Q adds a good 50 pounds well below the aircraft center and still handles much like the tail dragger. Also, from my experience, best to keep the flying CG closer to the front of the envelope than the rear. My 2 cents.

Cheers,
Jay Scheevel, Tri-Q2 N8WQ, 201 hours 


On Feb 9, 2022, at 7:28 PM, Ian Ashdown <ian.ashdown@...> wrote:

I bought that download too.  I’m sure it’ll be useful at some point.  What is slightly aggravating is that the parts were obviously modeled in SolidWorks, so why not offer a SolidWorks  or .stp download.  I’d have paid a little more for that, but now I just have to model the parts all over again . . . in SolidWorks!

In the end I think the design of engine mounts are going to be driven by the type of AV Mount I select ( does anyone have any recommendations) and the spacing off the firewall, driven by the balance of the lighter engine.  I’m still not sure if the effect of moving CofG a few points rearward would be a positive or a negative.  I think negative as pilot, passenger and ‘luggage’ are all aft of the CofG, it may limit the max load capacity.

Then there is the question of the ‘thrust line’. I think I’d like to raise it (from the O-200 WL position)  for better packaging, but I’m not certain yet.  Would raising the thrust line 1”- 1.6” create handling issues?  I don’t know what the aircraft vertical CofG height is, maybe it’s in some of the documentation . . .

Lots to figure out!

Ian
SoCal


Anthony P
 

Ian, if the silencer (muffler) is NOT an integral component of a sensitive tuned exhaust, I would ditch it.
The Q2 is not a certified aircraft, nor is it an LSA.  You can do stuff like this.

I don't know of anyone in the states that has a muffler on their Q2 or Dragonfly.  Maybe someone will speak up.
There are 4 individual runner systems, 2 into 1 on each side systems, and 4 into 1 systems out there flying.

Seems like it would be pumping a lot of heat into the cowling anyway.
I think you're going to have to push this engine pretty far forward, and based on your CAD image, that would put a big bulge forward on the lower cowling to fit (and provide cooling clearance) the stock muffler.

--
Q2 N86KL


Ian Ashdown
 

Hi Mike,

“So the Q200 is very nose heavy as built.”  That the kind of information I’ve been hoping for!  The Rotax is at least 50lbs lighter than the O-200 and the way I think I’m going to manage the fuel in the Header Tank, I will be about 75lbs lighter forward of the CofG.  I was planning to place the battery wherever it helped best with balance.  I’m not sure which battery I’ll be using yet, I probably should start looking.  I see some people are using Varley (race car battery) which has very good energy density, but there are some very good lithium batteries available these days.

Ian


Jay Scheevel
 

Hi Ian,

 

There is a lot of good information in the files section of this group. Have a look at the folder: https://q-list.groups.io/g/main/files/Weight%20&%20Balance

 

I just added my spreadsheet that I created for my plane as I was building and still use today. It is based on components. I would do W&B on the scales periodically as I was building so could determine whether my estimates of component weights and moment arms were going as planned, then make any course corrections earlier in the build, rather than wait until the end of the build process. You will see several “scratch” calculations on the right side of the component spreadsheet that gave me the data to do corrections to the individual components in the sheet. By the time I got around to final measurement of W&B, there were no surprises. It was a non-event.

 

You will also find at the bottom of the JRS_test_W&B sheet, there is a graph of the W&B with a snail trail of W&B as it changes throughout the flight as I burn off fuel. This is useful to know where you are in the envelope at takeoff and landing. All of my flights are nearer the forward end of the envelope in practice.

 

I have two EarthX ETX680C batteries mounted on the sidewall behind the passenger seat. They are small and together weigh about 7 pounds. I have been using them for 3 years now and they have been trouble free and reliable. I have electrical system “spike” protection, in addition to the BMS built into the batteries themselves, and I use a B&C external 40 amp NippoDenso type of alternator and a B&C regulator which also keeps the charging current pretty “clean”.

 

Cheers,

Jay

 

From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Ian Ashdown
Sent: Thursday, February 10, 2022 8:51 AM
To: main@Q-List.groups.io
Subject: Re: [Q-List] Q2/200 Engine mounts

 

Hi Mike,

“So the Q200 is very nose heavy as built.”  That the kind of information I’ve been hoping for!  The Rotax is at least 50lbs lighter than the O-200 and the way I think I’m going to manage the fuel in the Header Tank, I will be about 75lbs lighter forward of the CofG.  I was planning to place the battery wherever it helped best with balance.  I’m not sure which battery I’ll be using yet, I probably should start looking.  I see some people are using Varley (race car battery) which has very good energy density, but there are some very good lithium batteries available these days.

Ian