Power
John,
Yes, it's about 95 more watts that I can comfortably push for a burst sprint. I only did this in passing I will repeat it this summer more formally. But that's mighty encouraging no?
Here are the details for this completely unscientific comparison; and my plans in this area for the summer.
First, I do not have a direct power meter on the trike nor can I configure it for one as currently built. So I use a cycleops powercal heart rate based power meter to compare the trike to other bikes. I have historical data with the powercal that lead me to trust it's average readings for efforts over 15-30 secs. By direct comparison I found it to be within 2% of a crank based meter and others have achieved similar results so I trust the readings for gross comparisons of vehicles. The powercal is very useful for things like that because it's portable. If you use it with the same rider on the same day; I feel you can safely compare the results. I don't know that I would use it to calculate CdA and Crr because I do not trust the instantaneous data yet. The readings are best considered"crank" readings. If there was a massive power loss between the pedals and the wheel; the powercal isn't going to show that without a speed reading to plot it next to.
With the trike mounted on this trainer right now I can push 385 and hold that steady for a 45-60 second sprint then it starts to fluctuate; winter has trashed my cardio or I would do a 5 minute stress test. I put the Silvo on the same trainer and was messing around and decided I was warmed up enough to do a sprint to see how well I had the handle bars dial in, I was actually testing for tendon pain from the brake cable. When I held 480 that caught me off guard; so I redid the test about 10 minutes later and yep 480 (rounding down to nearest 5). That shows me one solid fact; the Silvio's triangle works to give me a rigid pedaling platform in a way the trike boom never can.
For background, the trike is pretty dialed in but it has some unique characteristics so drawing a conclusion against trikes in general might not be appropriate. It's a Catrike 700, 16in model with custom 20in wheel mounted that alter the geometry and raise the bottom bracket 1 full inch. It has a Mountain drive on the front, a custom triple idler and an N360 continuous variable hub on the back a 58T ring pusing a 20T sprocket. At 48lbs, I've had it up to 60mph down hill at 110rpm and I can hold 20 - 25mph in a flat ground 2 minute sprint; cruising speed is 17-18 mph. All and all it's pretty efficient for what it is. Average rides in this area are 2500-3000 ft of climbing average gradient are 4-14%. So lots of up and down. A the typical 50 mile ride will net an average trip speed of 15.5mph. Climbing speed is the Achilles of this trike. Took two years to dial that all in. Time for a new project... hello Silvio
So back to the comparison. On the trainer I guess/attribute the power loss on the trike to the flex in the seat and flex in the boom, both of those inhibit my ability to maintain a powerful mashing stroke on the pedals. I can spin a nice high power rating but a sprint for me is still about mashing down on the pedal as hard as I can for as long as I can. At those high mashing level; the front boom pogo and seat bounce eventually interferes with the pedal stroke and form.
For the Silvio it should be said that the trainer is giving me near perfect posture; no power lost to balance, and a solid arm bracing. The only loss I can feel on the trainer came from the bouncing of the rear suspension as that's set pretty loose right now. Body bounce felt to be about 1/3 to 1/2 of what I get from the trike seat. Not sure how that could be measure other than subjectively.
When I get on the road the Silvio power output will probably suffer from my lack of skill with MBB at this time, I'm not going to be able to brace nearly as steady and balance etc. I have a Stages crank arm power meter in the plan. I will order that when the tax return arrives. That meter will spend the entire summer on the Silvio and I'll be collecting data on every ride. I suspect at this time that my power output will have a lot to do with my upper body strength and ability to maintain a stable front end to power against. I also suspect that my polished SPIN power output will be unique and separate from my MASH power output; so far those feel like they will be vastly different aggregate muscle groups (which sounds great to me for distributing effort). If the data from a middle age, out of shape rider is interesting to your design efforts I'll make it available. I should be getting a minimum of 2000 miles in this year; hoping to push that up closer to 5000 if the weather is good.
Lastly, because of things like the bullhorns and extension, and figuring out where to hang things like water bottles whether to dish the wheels etc, I've decided to try and "Chung" this thing pretty extensively this summer as time allows. I've identified a circular test loop nearby that is safe to ride at after dark, (I live in the heart of the North America Jet Stream so wind free riding only exists after sundown). The plan is to get a baseline CdA and Crr readings over a couple of weeks at start of the season while I learn to ride. Once those readings stabilize I will know that my riding form is consistent, then I'm going to tweak the bike 1 variable at time until I figure out all the optimal settings for me. I'm curious only to learn which changes make "gross" alterations in the performance. Basically I want to make sure I don't adopt anything flat out dumb with my riding form or bike geometry. For example what exactly will adding a 50mm extension do to the performance, if it makes the bike look cool but messes up, CdA, Crr, and ability to maintain Power input I want to know that. I might choose cool looking or comfort over performance, but I prefer those to be conscious decisions. Given all the info you made available; it shouldn't be too hard as most of the important stuff about riding positions is already documented.
So that's the plan we'll see how reality plays out.
If there is anything specific you'd want tested on the Silvio platform If it's within our abilities and means we'd be happy to put the time in, having goals always leads to more riding so that's a good thing.