Aviomania - Viking First Impressions

PW_Plack

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jm-urbani;n1128520 said:
how can they get 130 hp at 66% rpm out off a 1.5l honda engine without any turbocharger ?
The normally-aspirated (atmo) Honda S2000 was SAE rated at 120 HP per liter, so it's not impossible. But that car had a much higher redline. Honda rates the 1.5L engine in the fit at 130 HP at 6000 RPM, with a redline of 6800 RPM. Working the math backward from the Viking website, the graph shows 130 HP at 2350 prop RPM; that's 5475 engine RPM, which is 80% of the engine manufacturer's published redline.

He is apparently uprating redline to 8300 RPM.
 

jm-urbani

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I won't believe them until I see the engine on a dyno
have a look again honda says 130 hp @ 6600 rpm, not 6000
how come on an atmos viking they could get the same power @ 5450 rpm ?
 
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PW_Plack

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jm-urbani;n1128625 said:
I won't believe them until I see the engine on a dyno...have a look again honda says 130 hp @ 6600 rpm, not 6000.
Sorry, I was working from memory. Thank you for the correction. The discrepancy in percentage of redline is unchanged, however.

I will be mildly surprised if we ever see this engine on a dyno.
 

jm-urbani

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Don't be sorry @ all i did not want to proove you were wrong but only to go on thinking together
in my opinion, but it is only an opinion it is really difficult to get 130 cv out of this kind of engines
 

Vance

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It is my observation that most engine suppliers exaggerate the horsepower.

I have spent a lot of time operating engine dynameters and getting consistent readings is not a simple thing.

I once had an 89 horsepower Harley Davidson Sporster that in a magazine article they decided it was making 112 horsepower because it was so fast??? I told them it was a certified dynamometer and they still just made it up.

My 140 horsepower unfaired Fuel Sporster supposedly needed 200 horsepower to set the 199.9 mile per hour record it set. Again it was a certified dynamometer. They were just so used to bar talk numbers that reality seemed unrealistic.

If I was marketing an engine I don't know what I would do.

In my opinion horsepower is just bar talk and the reality is in how it performs. Horsepower has been so distorted and exaggerated that advertised horsepower is no longer a useful metric.

If you can get an engine to breathe more rpm makes more power and less rpm makes less power.

More compression or a better combustion chamber may make a small difference.

A useful way to estimate potential horsepower for a normally aspirated engine on gasoline is one foot pound of torque per cubic inch times the RPM divided by 5252. If it is supposed to make a lot more it is likely a fantasy.

Example: 1.5 liter engine is 91.5 cubic inches times 6,000rpm=549,000 divided by 5,252=104.5 horsepower.

My Lycoming 320 cubic inches times 2,700rpm=864,000 divided by 5,252=164 horsepower.

For the Sporster 89 cubic inches times 5,500rpm divided by 5,252=90 horsepower.
 

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dinoa

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Even worse is the weight game even though it only takes a scale to measure.
 

PW_Plack

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Vance;n1128649 said:
In my opinion horsepower is just bar talk and the reality is in how it performs.
The SAE standards used by auto manufacturers in the US for stating HP are of some value in achieving apples-to-apples comparisons, but in road vehicles with stepped-ratio transmissions, a wide torque band may improve real-world acceleration numbers. In an aircraft, if the prop and gear ratio are optimized, HP should accurately predict thrust potential, and torque at RPMs below full power shouldn't make much difference beyond improving response.

Up until the late 1960s, auto HP was a simple calculation based on displacement (or marketing department fantasy) which was of little real-world value. For a while in the 1970s, some horsepower was radically understated in the face of escalating insurance company surcharges. Auto manufacturers now quote SAE net, installed HP, which is supposed to be measured with engine-driven accessories such as power steering in operation. It might be possible to improve peak HP in an auto conversion beyond the manufacturer's SAE claims through optimization of intake and exhaust systems, elimination of accessories not needed in an aircraft, and without the impediments of emissions and MPG constraints.

But I would not expect Eggenfellner or any other low-volume converter to have better intake/exhaust or camshaft science than Honda when tuning Honda engines. I'm also skeptical of the claims of aftermarket engine accessory manufacturers.

I have more faith in dyno numbers if the salesman isn't the one running the dyno and reporting the results..

The best yardstick we can likely have in aviation is the advice of the prop manufacturers. They know what thrust should be generated by various combinations of length, pitch and RPM, and should be in a good position to debunk bogus HP claims.
 

Resasi

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Joe, good to hear that after two sad events you seem to have sorted the problem. Congratulations for that and carrying on.
 

Joe Pires

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Resasi;n1129203 said:
Joe, good to hear that after two sad events you seem to have sorted the problem. Congratulations for that and carrying on.
Thank you. Things continue to progess well. Just returned from Zephyrhills where I visited with Greg Spicola, and half a dozen other gyro guys. 182 mile roundtrip. New Years eve I flew to Wauchula and back a 200 mile round trip.
​​​
While cross country flying is not my primary goal it's good to get the experience and develop the confidence.
 

fara

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Joe Pires;n1129229 said:
Thank you. Things continue to progess well. Just returned from Zephyrhills where I visited with Greg Spicola, and half a dozen other gyro guys. 182 mile roundtrip. New Years eve I flew to Wauchula and back a 200 mile round trip.
​​​
While cross country flying is not my primary goal it's good to get the experience and develop the confidence.
Ah I missed that. I was at our shop right behind the airport from 1 to 6 pm working on latch lock design for the AR-1 canopy. Next time
 

RMM

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@Resasi...thanks for bringing this thread back on topic. Very good news from Joe indeed. Wish him hundreds hours more of happy flight. Joe, please keep us up to date from time to time on your Aviomania. What a gorgeous machine. Congratulations.
 

Joe Pires

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Just got back from a one hour flight with Laura. This is the longest flight with a passenger to date. I was curious to do a fuel burn test. We flew conservatively with rpm between 5200 and 5400. We were doing about 65 or so and we burned 6.5 gph on that trip. Ed is welding up an additional spun aluminum tank that we will add to the machine for another 2.49 gallons which will give us a usable 13 gallons and really give us the range we want. So far my 100 ish mile trips have been between 1 hr and 16 minutes to 1 hour and 24 minutes so the additional tank will give us confidence in trips of that length even if we push the speed a little.

I now have taken passengers up to 200 pounds off my grass strip and at current temps performance is not an issue. Today's take off with Laura had me air-born in about the same distance I normally get off with my single place.

I have decreased my prop pitch and now occasionally see 6200 rpm. There is a bit left still but I am not likely to change till I see the results of thinner summer air.

There was questions on how I solved the overheating issue. Originally Jan had only a bottom vent that went into a reservoir. The problem we kept experiencing was the air had to push out the oil in order to vent. He finally added an upper vent but unfortunately he vented it into the same reservoir. The problem was the lower vent which he relied on for the oil to return did not allow the oil to return. its location behind a gear stopped the return. The fix was fairly simple. I plugged the lower vent. Then to make sure the upper vent actually vented we put the finger of a rubber glove over the vent hose and we could see it inflate. It also however vented oil. I moved the reservoir high on the mast so that the oil would develop some back pressure as it came out and flow quickly back in. Before the change, after a 30 minute flight I had 9 of the 12 oz of gear oil in the reservoir. Also the gear oil actually took days to run back into the gear box. Now I have about 2.9 ounces leaving the gearbox and it drains back in within 10 minutes. It is possible that the 2.9 ounces is just a result of having 2.9 ounces more than the gear box wants, but I am not going to fret that. I have reached stable gearbox oil temps that run between 185 and 195 degrees on average. I have done 4 gearbox oil changes during this process and do not seem to be making any metal.

The least favorite part of the Aviomania is the cramped pod. You can see by the one of the attached photos the legs of a tall pilot. Even I find the pod restrictive. The pod I have is not the current production pod. I have not seen the new one but Nicolas says its bigger. He has also offered to send me a new one for the cost of freight. I plan to take him up on that offer.

I continue to be very happy with the wide-chord blades from Ernie. Laura has flown in every two place gyro that will take her up. Shes a bit of a gyro tramp but I love her. She says its the smoothest of any gyro she has flown in. Here are some pics.
 

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All_In

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Hi Joe
Glad to hear you got the overheating problem solved and are enjoying her now.

The new pods are larger than your production prototype and I'd take him up on the offer. Not sure how he affords it?

Nicolas is a generous man as it costs him to upgrade for free.

When he upgraded the G1sa gas tanks from 8 gals to 10 he sent ALL the US owners new tanks for free.
He also sent a 2nd new enlarged pod to a two place customer who ordered, paid for and received the old style pod for free.
He sent me all new body parts to upgrade from the G1sa to make it a modern G1sb all for FREE just because he did not want me to flying the old style either.
 

CLS447

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That's great news, Joe ! You need to update your avatar. Have fun !
 

j bird

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John, is there a G1sb flying on the west coast ?
 

Joe Pires

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The reason for my wanting a two place is that I wanted to fly anyone who wanted to fly with me from my grass strip. I have seen the performance of the 100 HP Rotax on my field and gyro's struggle to get out with two full size people. Today I took my largest passenger to date about 220 pounds, and I killed it. I now know the technique that works best for my machine and with the extra power of a 130 horse and Ernie's heavy lift blades I had nearly had nearly 500 feet at the end of the runway and I had backed off the power by that point. Granted it is not yet summer but I feel that I am well on my way to realizing what I had hoped for.
 

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Aviomania

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I am happy you solved the gearbox problems!!! the new pod will look much better !!!!!
 

RMM

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Great to hear. Now we can put to rest the “Rotax Only and Nothing Else” mantra. Alternatives are good for aviation. It is unfortunate that your Viking saga took such turns and delays. But those days look like they are well and truly over. Wish your Viking Honda serves you well for many seasons. Hope others benefit from your struggles and ultimate success.
 

All_In

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RMM;n1134614 said:
Great to hear. Now we can put to rest the “Rotax Only and Nothing Else” mantra. Alternatives are good for aviation. It is unfortunate that your Viking saga took such turns and delays. But those days look like they are well and truly over. Wish your Viking Honda serves you well for many seasons. Hope others benefit from your struggles and ultimate success.
Joe Knows what he is doing that is fro sure.
Aviomania experience changed Nicolas thinking to only selling Rotax engines.
We have sold 14 but only 2 with an alternative engine are built and flying and 5 Rotax's are built in a couple of weeks and ready to fly. Nicolas told me he would rather have them flying than just sell them.
Also you have to adjust the center of gravity with Nicolas only estimating where it should be has he only has made them PERFECT for Rotax's which they are designed and test for.
That is why you can no longer buy an Aviomania without and engine unless you have a used Rotax and send him a picture of int and a picture of the serial number.
 
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