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GPH and KTAS at 8000ft and 55% power

Goran

Member
After Oshkosh this year, I will make my decision to either go for RV-10 or Sling TSi kit. This is a question for all of you flying RV-10. According to the specs, the RV-10 has a range of 1000 sm, at 55% power and 8000ft with IO-540. I would like to know what is the KTAS at 8000ft and 55% power? Also what is the fuel GPH at this settings? Thanks,
 
I never computed the % of horsepower but at 8000' I'll be full throttle burning 13.5 GPH and doing 172+ ktas.

-Marc
 
I usually fly more like 10,000’ for those low power settings where 55%, lean of peak, I get 160 ktas on 10 gal/hr.
 
36 LPH or 9.5GPH

Not 8000, but the -10 loves flying high,

161knts @ 9.5 GPH, Dual SDS Ignition, LOP, 55% power

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250 hp O-540, 160 knots 10.5 gph. I suggest you sit in both aircraft. The Sling looks great on paper (if you have more than double the money) but when I saw it at SnF I was amazed that it seemed like it had almost no forward visibility and would not be suitable for any unimproved runways.
 
at 8000', I cruise at 165 KTAS on 10.5-10.8. Same speed at 14,000 is low 9's GPH.

Adjustable advance EI and tuned injectors.

Larry
 
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Wow, thank you all for info you provided. This is exactly what I needed.

Not 8000, but the -10 loves flying high,
161knts @ 9.5 GPH, Dual SDS Ignition, LOP, 55% power
I really like the SDS product and I've been following their YouTube channel for a while now.

I usually fly more like 10,000’ for those low power settings where 55%, lean of peak, I get 160 ktas on 10 gal/hr.
All right, this is what I wanted to see. Thanks.

250 hp O-540, 160 knots 10.5 gph. I suggest you sit in both aircraft. The Sling looks great on paper (if you have more than double the money) but when I saw it at SnF I was amazed that it seemed like it had almost no forward visibility and would not be suitable for any unimproved runways.
I hear you. I reserved me a spot for a demo flight with both Sling TSi and RV-10 at this year Oshkosh. Sling TSi is way better on gas mileage, pricewise. The difference between 8gph of autogas and 10 gph of 100ll is roughly $26 per hour. Multiply that by about 100 hours of flying a year, and that is $2600. In 10 years, that is $26 000 ... Offset to that is, 1200 hours TBO on Rotax 915is engine. Let alone the fact, that Rotax 915is engine is a toy comparing it to IO-540. With all that said, I am leaning towards RV-10.

Once again, thank you all.
 
The 540 runs fine on Mogas if you want.

The ROC on the Sling isn't anywhere close to an RV-10 if that's important.

To match the Sling's 148 KTAS, a good RV-10 will burn within a whisker of 8 gph at 10,000 feet LOP.
 
The ROC on the Sling isn't anywhere close to an RV-10 if that's important.
What is ROC? I am new to all this terminology and learning ... Thanks.

To match the Sling's 148 KTAS, a good RV-10 will burn within a whisker of 8 gph at 10,000 feet LOP.
That is very interesting to hear. I like your fuel injections products. I am ways away from buying an engine, however I am trying to educate myself about all available engine/avionics/airplane options. Are you going to be at Oshkosh this year?
 
What is ROC? I am new to all this terminology and learning ... Thanks.

That is very interesting to hear. I like your fuel injections products. I am ways away from buying an engine, however I am trying to educate myself about all available engine/avionics/airplane options. Are you going to be at Oshkosh this year?

ROC= rate of climb

We are too busy to go to Oshkosh and not sure what restrictions would be in place at that time to re-enter Canada.
 
same as lr172

same for me, pretty much the same as Larry's numbers.
I do burn 91 Octane E10 most of the time in a 8:5 to 1 IO 540.
I don't see a difference in any of the performance numbers if anything, I am able to lean just a little more on mogas.
 
One more data point...

Here's my performance numbers running LOP & WOT.
 

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Here's my performance numbers running LOP & WOT.

What are the pink cross hairs for? I have never seen those on a G3X. I really miss the CDI cross hairs that the GRT has on my 6 and wonder if that is their role. Much easier to use than the std CDI's on the G3X.

Larry
 
What are the pink cross hairs for? I have never seen those on a G3X. I really miss the CDI cross hairs that the GRT has on my 6 and wonder if that is their role. Much easier to use than the std CDI's on the G3X.

Larry

Dual Cue Flight Director. Try it out: Menu > Menu > Setup > Flight Director > Single Cue/Dual Cue
 
Sling tsi or rv10

Mojogrip did a comparison between the two planes, ( check it out on YouTube)when I saw it I thought it was like comparing apples to oranges. The two planes are simply different in so many ways. The claim of the two being the same at higher altitudes, I don’t believe. I have yet to go for a flight, but one day I’ll go.
Vans and TAF are both great folks, Jean at Torrance, the chief test pilot and demonstrator is a fantastic person with so much knowledge of the plane. Make sure to do that demo flight, and talk to him at Osh; but keep in mind the kits come from South Africa, shipped to Torrance and is than shipped to each customer. We are talking months from order to delivery, Vans is in Oregon and if your missing a part or need a replacement it’s far less expensive and time turnaround.
I will end with this, the sling tsi is a fantastic plane but if you want performance the RV-10 is the plane, the sling tsi is easier to build, as it’s all pop rivets versus rivets for the RV and hence can be built faster than the RV. And this is important, the plans for the sling are lacking in so many ways. If your experienced it’s easier to get through, but it’s nothing close to the instructions and detail Vans has mastered in their manuals.
Send me a PM if you have any further questions.
 
my thoughts

I would say these numbers depend on temperature and weight.
Everyone has posted the right numbers but I have also seen 152-155 depending on temperature and weight at 10,000 ft. LOP. Flying at max gross on a hot day in July to Oshkosh can be around 155 and then you hit moderate turbulence over Wyoming and watch the speed go 150-152.
If you only have one or two people in the plane at 8500 ft. LOP it can easily be 160-170 kts, especially if it is cooler out.

I leave my speed at 158kts on Foreflight for flight planning and it is really close for almost all conditions and I always fly LOP.

Spend plenty of time in each one at the weight you will fly your typical mission.

Fun dilemma to have......good luck.
 
I would say these numbers depend on temperature and weight.
Everyone has posted the right numbers but I have also seen 152-155 depending on temperature and weight at 10,000 ft. LOP. Flying at max gross on a hot day in July to Oshkosh can be around 155 and then you hit moderate turbulence over Wyoming and watch the speed go 150-152.
If you only have one or two people in the plane at 8500 ft. LOP it can easily be 160-170 kts, especially if it is cooler out.

I leave my speed at 158kts on Foreflight for flight planning and it is really close for almost all conditions and I always fly LOP.

Spend plenty of time in each one at the weight you will fly your typical mission.

Fun dilemma to have......good luck.

The numbers that I posted are pretty much the same when solo or full gross. I have done several trips at gross and it is very repeatable, though the GPH may be .1 or .2 higher but in the range.

I definitely have days where I am a few knots lower or higher than normal and attribute that to up or down drafts. Very noticeable on the trips to Denver where I get 20 knot swings. Unfortunately it seems 80 down draft and 20% up draft.

I don't see appreciable variability based upon temps and I fly as low as 0F. This makes sense, as cooler air requires more fuel and produces more power. However air fuel mixture ratios are the key and these don't really change with density when adjusted properly, though I can tweak my advance to match the AFR.. While max power will be lower in warm air, the BSFC should be similar across a wide temp range, producing consistent MPG values. Cimb is another animal. I climb at almost twice the ROC in winter vs hot summer. Note, winter for me is <30F.

At 8000', I have never been below 160 KTAS (Winter, summer, solo or gross) if flowing 10.5-11, except in the big downdrafts near the rockies and those are cyclical with somewhat normal KTAS in between, though I have had extended downdraft pressure with speeds below 160 in that area. I have high confidence that is mountain wave induced and not a performance issue.

Larry
 
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I leave my speed at 158kts on Foreflight for flight planning and it is really close for almost all conditions and I always fly LOP.
Thanks for your comments Scott. What is your GPH at this speed? I assume you fly 8000 or higher feet with this speed. Thanks.
 
250 hp O-540, 160 knots 10.5 gph. I suggest you sit in both aircraft. The Sling looks great on paper (if you have more than double the money) but when I saw it at SnF I was amazed that it seemed like it had almost no forward visibility and would not be suitable for any unimproved runways.

Have you sat in a Sling TSi? Having spent about 50 hours in one so far I can tell you it has outstanding visibility. The clever design of the seat means it accommodates people of different heights very well. As it slides back, the seat height lowers, as it slides forward, it raises. I'm 5' 7" and my friend is 6' 3", and we were both very comfortable in it flying from Idaho to Sun-N-Fun and back.

As for unimproved runways, being from South Africa, Slings been flying in and out of unimproved runways for many, many years.

The "more than double the money" comment is quite curious, too. For build-assist, I contacted several RV-10 build centers and, for a comparably-equipped RV-10 (that means ballistic parachute, electronic engine control, 3-blade prop, high-quality interior, Garmin panel, etc.), the quotes were $75k to $100k higher than what I'm paying for my Sling TSi. If building by yourself, the Sling is faster to build with its pulled rivets.

Bottom line, they're both fine airplanes. You'll be happy with whichever you choose.
 
Here are my numbers accumulated over 1000+ hours downloaded from my G3X. All LOP set for best speed not best MPG. And yes, my pitot static is within 1kt. 90% of my flying is cross country with just myself and my wife with very little baggage. ROP I burn about 4-5 GPH more and gain 4-8kts.



6K 11.9 169 8K 11.7 168 9K 11.4 167 10K 11.1 166 11K 10.7 165
 
Here are my numbers accumulated over 1000+ hours downloaded from my G3X. All LOP set for best speed not best MPG. And yes, my pitot static is within 1kt. 90% of my flying is cross country with just myself and my wife with very little baggage. ROP I burn about 4-5 GPH more and gain 4-8kts.



6K 11.9 169 8K 11.7 168 9K 11.4 167 10K 11.1 166 11K 10.7 165
This is really good info. Thanks Bill.
 
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